app_voicemail/app: Remove test events that were duplicated by r421059

Moving the test event raised when a file is played back (which occurred in
r421059) broke the ever loving snot out of the voicemail tests. This caused
duplicate test events to get raised, as app_voicemail and main/app were raising
events prior to call ast_streamfile. The voicemail tests did not enjoy getting
multiple events.

Since raising the playback event in ast_streamfile is far more useful to the
vast majority of tests, this patch keeps the call there and simply removes the
extraneous calls that duplicated the event.
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Merged revisions 421125 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 421164 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@421165 f38db490-d61c-443f-a65b-d21fe96a405b