Add include guards for builds without dbus
Add include guards for builds without dbus

This commit adds include guards around a QDBusInterface include added in
commit 15831dbca without the appropriate guards.

Lartza/mumble,Lartza/mumble,Lartza/mumble,Lartza/mumble,Lartza/mumble,Lartza/mumble,Lartza/mumble,Lartza/mumble