Don't convert numbers and booleans to strings.

Before this change if a variable was of type int or bool and the variable was referenced
by another variable, the type would change to string.

eg. defaults/main.yml
```
PORT: 4567
OTHER_CONFIG:
  secret1: "so_secret"
  secret2: "even_more_secret"

CONFIG:
  hostname: "some_hostname"
  port: "{{ PORT }}"
  secrets: "{{ OTHER_CONFIG }}"
```

If you output `CONFIG` to json or yaml, the port would get represented in the output as a
string instead of as a number, but secrets would get represented as a dictionary.  This is
a mis-match in behaviour where some "types" are retained and others are not.  This change
should fix the issue.

Update template test to also test var retainment.

Make the template changes in v2.
Update to only short-circuit for booleans and numbers.

Added an entry to the changelog.

lib/ansible/utils/template.py

@@ -31,6 +31,7 @@ import datetime
 import pwd
 import ast
 import traceback
+from numbers import Number
 
 from ansible.utils.string_functions import count_newlines_from_end
 from ansible.utils import to_bytes, to_unicode
@@ -81,6 +82,11 @@ class Flags:
 
 FILTER_PLUGINS = None
 _LISTRE = re.compile(r"(\w+)\[(\d+)\]")
+
+# A regex for checking to see if a variable we're trying to
+# expand is just a single variable name.
+SINGLE_VAR = re.compile(r"^{{\s*(\w*)\s*}}$")
+
 JINJA2_OVERRIDE = '#jinja2:'
 JINJA2_ALLOWED_OVERRIDES = ['trim_blocks', 'lstrip_blocks', 'newline_sequence', 'keep_trailing_newline']
 
@@ -109,7 +115,6 @@ def lookup(name, *args, **kwargs):
 def template(basedir, varname, templatevars, lookup_fatal=True, depth=0, expand_lists=True, convert_bare=False, fail_on_undefined=False, filter_fatal=True):
     ''' templates a data structure by traversing it and substituting for other data structures '''
     from ansible import utils
-
     try:
         if convert_bare and isinstance(varname, basestring):
             first_part = varname.split(".")[0].split("[")[0]
@@ -123,10 +128,13 @@ def template(basedir, varname, templatevars, lookup_fatal=True, depth=0, expand_
                 except errors.AnsibleError, e:
                     raise errors.AnsibleError("Failed to template %s: %s" % (varname, str(e)))
 
-                if (varname.startswith("{") and not varname.startswith("{{")) or varname.startswith("["):
-                    eval_results = utils.safe_eval(varname, locals=templatevars, include_exceptions=True)
-                    if eval_results[1] is None:
-                        varname = eval_results[0]
+                # template_from_string may return non strings for the case where the var is just
+                # a reference to a single variable, so we should re_check before we do further evals
+                if isinstance(varname, basestring):
+                    if (varname.startswith("{") and not varname.startswith("{{")) or varname.startswith("["):
+                        eval_results = utils.safe_eval(varname, locals=templatevars, include_exceptions=True)
+                        if eval_results[1] is None:
+                            varname = eval_results[0]
 
             return varname
 
@@ -323,10 +331,20 @@ def template_from_file(basedir, path, vars, vault_password=None):
 
 def template_from_string(basedir, data, vars, fail_on_undefined=False):
     ''' run a string through the (Jinja2) templating engine '''
-
     try:
         if type(data) == str:
             data = unicode(data, 'utf-8')
+   
+            # Check to see if the string we are trying to render is just referencing a single
+            # var.  In this case we don't wont to accidentally change the type of the variable
+            # to a string by using the jinja template renderer. We just want to pass it. 
+            only_one = SINGLE_VAR.match(data)
+            if only_one:
+                var_name = only_one.group(1)
+                if var_name in vars:
+                    resolved_val = vars[var_name]
+                    if isinstance(resolved_val, (bool, Number)):
+                        return resolved_val
 
         def my_finalize(thing):
             return thing if thing is not None else ''