Fix silly typo (bug #3483)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4946 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -6887,7 +6887,7 @@ static char no_history_usage[] =
 static char history_usage[] = 
 "Usage: sip history\n"
 "       Enables recording of SIP dialog history for debugging purposes.\n"
-"Use 'sip show hitory' to view the history of a call number.\n";
+"Use 'sip show history' to view the history of a call number.\n";
 
 static char sip_reload_usage[] =
 "Usage: sip reload\n"