Fix compilation error introduced in r388815

r388815 didn't not cleanly apply the intended patch. As a result, app_voicemail
had a small issue in that it didn't compile. Whoops.

This patch pulls in the correct variable declarations such that gcc can figure
out what 'urgent_index' is all about.


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/10-digiumphones@397704 f38db490-d61c-443f-a65b-d21fe96a405b