rhythmbox: Fix startup crash and plugins
This update fixes the following issues for rhythmbox:
- 765805: Fix crash at startup and plugins
- 765943: Fix plugins and disable the magnatune plugin
- Submitted by Gary Ching-Pang Lin (gary_lin)
Fixed bugs
bnc#765805
rhythmbox doesn't start
bnc#765943
most rhythmbox plugins don't work