Fix one NPE in tethering setting

Once we not declare BT feature, go Setting->more->tethering
will trigger this NPE.

Change-Id: I4736e7bade261475acda74e26250a81452018ffa
Signed-off-by: Jianzheng Zhou <jianzheng.zhou@freescale.com>
Settings: Fix the memory leak in Settings

Fixed the memory leak in both InstalledAppDetails

Change-Id: I3520b3c1fe1bf98e3baec2ee989eb215164a7cf2
Signed-off-by: Zhijun Peng <pengzhj@marvell.com>
Fix WifiManager melory leak, change context to getApplicationContext

Change-Id: Iba90045c4e31537defeec7a6f965d3b764065864
Signed-off-by: annieyu <annieyu@huaqin.com>