CMFM: Fix change to root when initial directory not exists

Fix also R.string.msgs_settings_invalid_initial_directory string for default string.xml file

Change-Id: I35ddf7f1ca2b250638ea96bfee894de9f07ed5b9
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
Merge "CMFM: Fix change to root when initial directory not exists" into cm-10.1