Reduce chance of mistakes with unsafe_shell check during refactor

Code like this:

if cond1 and cond2:
    pass
elif cond1:
    pass

Has a hidden dependency on the order that the conditions are checked.
This makes them fragile and subject to breakage during refactors.
Rewrite the code like this:

if cond1:
    if cond2:
        pass
    else:
        pass

The nested structure makes the ordering explicit and less likely for
someone to break the code when they refactor.

lib/ansible/module_utils/basic.py

@@ -2606,10 +2606,10 @@ class AnsibleModule(object):
             if use_unsafe_shell:
                 args = " ".join([shlex_quote(x) for x in args])
                 shell = True
-        elif isinstance(args, (binary_type, text_type)) and use_unsafe_shell:
-            shell = True
         elif isinstance(args, (binary_type, text_type)):
-            if not use_unsafe_shell:
+            if use_unsafe_shell:
+                shell = True
+            else:
                 # On python2.6 and below, shlex has problems with text type
                 # On python3, shlex needs a text type.
                 if PY2: