Conditionally reject duplicate entries in applicationmap containers.

When reading from a config file, it's important to reject duplicates. Otherwise,
featuregroups will have ambiguity when pointing to applicationmap items. However,
when constructing the channel's current applicationmap, we don't care about duplicate
names since it's the DTMF that identifies a feature, not the name.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@390787 65c4cc65-6c06-0410-ace0-fbb531ad65f3