let mythtv-common suggest the debug symbols

This gives users backtraces that developers can make sense of on
the first crash. And hopefully helps with the automatic error
collector, too.
https://errors.ubuntu.com/?package=mythtv&period=month

Discussed at http://irc.mythtv.org/ircLog/channel/4/2013-08-23:17:10
17:10 until 19:22