Less invalidateOptionsMenu()

1. setAccount() and switchAccount() already call invalidation, so
   remove calls just after those two.

2. Settings changes do not change the back button, so don't reset the
   action bar button when settings change.

Discussed in b/6946182

Change-Id: I1b8e8d0caf1b20f33ee33c2dd59114597e767de8
2 files changed