Ensure global types in the config framework are initialized

If a config object was allocated but one of its global objects was
never encountered, then the global object's defaults were never
applied. Ensure that global objects are initialized properly upon
allocation instead of on configuration.

Review: https://reviewboard.asterisk.org/r/2866/


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/11@399564 f38db490-d61c-443f-a65b-d21fe96a405b