Prior to this commit, if anything at all went wrong in
switch_ivr_phrase_macro_event() we would generate a warning like this:

  [WARNING] switch_ivr_play_say.c:348 Macro [macro_name]: 'pattern_name' did not match any patterns

This is clearly misleading.  The natural thing to do on seeing that
message is to verify that the language files are there, and that the
pattern really does exist in that macro.  But none of that was usually
the problem.  The message would be generated if the language wasn't
found, or if the channel had gone away, for example.

With this commit, we verify that we actually tried looking for the
pattern before displaying the warning about the pattern not matching.