Update reboot and screenshot power menu drawables with xxhdpi versions

Change-Id: I59fff6cf1621f59662408b8223a6582cdb54049e
Don't start keyguard in an attempt to exit it.

exitKeyguardSecurely() will open the keyguard if it's currently disabled
by an app. As this is unwanted here (the user has either already
bypassed the keyguard or the keyguard isn't secure; otherwise he
couldn't click on a notification entry) and as the lockscreen already is
dismissed a few lines above, don't call exitKeyguardSecurely here.

Change-Id: I5582da350d8826e42f9edcd56845a59965865c8b
JIRA:CYAN-99
Fix FindBugs issues

IntProperty: Infinite recursive loop
SQLiteSession: Null pointer dereference
UsbStoreActivity: Null pointer derefence
LocationManagerService: No relationship between generic parameter and method argument
ActivityManagerService: Call to equals() comparing different types
ChooseAccountTypeActivity: Possible null pointer dereference
RuimRecords: Possible null pointer derefence

Change-Id: I9d631c50c30eb98e32cca5a5085513b6904db676