[analyzer] Rename callback EndPath -> EndFunction

This better reflects when callback is called and what the checkers
are relying on. (Both names meant the same pre-IPA.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171432 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed