when loadable modules are disabled, if someone tries to load a module that...

when loadable modules are disabled, if someone tries to load a module that does not exist, don't dereference a NULL pointer, just stop trying to load it...


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@40854 65c4cc65-6c06-0410-ace0-fbb531ad65f3