CRM-16373 - CRM_Core_Config - Simplify initialization, esp `templateCompileDir`

CRM-16373 - CRM_Core_Config - Simplify initialization, esp `templateCompileDir`

Generally, this commit removes some silly 1-line functions, misplaed
functions, duplicated steps, obvious comments, and expired comments.

There is a change in `templateCompileDir`.

The `templateCompileDir` had two different intialization blocks (in
different places), which likely arose from variations in the code-paths used
for memcache systems.  Both routines append a locale and create the dir.

This is redundant, and it unnecessarily forces us to resolve the locale
early during initialization.  But honestly we don't need to append the
locale until much later (when/if Smarty is first used).

There are a few oddballs who use `$config->templateCompileDir` and they may
see a slight change (working with the real templateCompileDir rather than
the locale subdir):

 * The cleanup. If this code causes a change, it will be an improvement:
   instead of cleaning the Smarty cache for one locale, it'll clean the
   entire Smarty cache for all locales.
 * Random temp files. The temp files seem to be transactional in nature
   (tied to the specific invocatoin) and not to the locale.