Remove unnecessary error message in app_dial.c

Remove unnecessary error message in app_dial.c

The error message for failure to stop autoservice after a gosub or macro call
during a dial was removed for macro while Asterisk 1.4 was still being actively
developed. The corresponding gosub error message was never removed.

(closes issue ASTERISK-19551)
........

Merged revisions 361329 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@361330 65c4cc65-6c06-0410-ace0-fbb531ad65f3