When trying to unload res_curl.so, warn about all dependent modules.

Before this, attempting to unload res_curl.so would warn you about the first
module it found that was dependent.  We now warn about all of the loaded modules
instead.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@373203 65c4cc65-6c06-0410-ace0-fbb531ad65f3