Fix a small typo in description in of Voicemail() application.

Issue 10170, patch by casper.


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@74316 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_voicemail.c

@@ -318,7 +318,7 @@ static char *descrip_vm =
 "           message. The units are whole-number decibels (dB).\n"
 "    s    - Skip the playback of instructions for leaving a message to the\n"
 "           calling party.\n"
-"    u    - Play the 'unavailable greeting.\n"
+"    u    - Play the 'unavailable' greeting.\n"
 "    j    - Jump to priority n+101 if the mailbox is not found or some other\n"
 "           error occurs.\n";