Mms: Fix QuickMessage mdpi/hdpi layouts

Fix https://jira.cyanogenmod.org/secure/attachment/12587/Screenshot_2013-09-15-22-59-37.jpg

Change-Id: I42131b0f997edb8f3ddbec758d861cd70f816b16
JIRA: CYAN-1605
Issue: https://jira.cyanogenmod.org/browse/CYAN-1605
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>