launcher3: Fix shortcut install/uninstall permission name

AOSP 4.4 has a public INSTALL_SHORTCUT/UNINSTALL_SHORTCUT permission.

Change-Id: I5cb5f9c6606bdfa5a50acbc1ae6a7ac0a83b1ac1
JIRA: CYAN-3201
Issue: https://jira.cyanogenmod.org/browse/CYAN-3201
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
LauncherModel : Ensure checkItemPlacement key casting

Ensure the key is casted correctly.

Change-Id: Id0ac5ab878d1d059c138ae294a3eff63bf0d858b