[krbdev.mit.edu #3286] Network Identity Manager - Fix module loading when en_US locale cannot be loaded

[Jeffrey Altman via RT]

The identity manager is designed for internationalization. However, it
only ships with modules for the en_US locale.   Designing modules for
other locales was beyond our thereach of available resources.  This
patch will force the use of en_US when modules matching the installed
user and system locales cannot be found.