Fixed issue with incomplete initialization of struct.
Changed to get the current voice properties, then modify then and set new ones.
Merge branch 'master' of https://github.com/mavlink/qgroundcontrol
Merge branch 'master' of https://github.com/mavlink/qgroundcontrol
Fixes for using unitialized variables reported by valgrind.
Merge pull request #791 from Susurrus/valgrind2

Cleanup some unitialized variable issues pointed out by Valgrind