appops: Fix an off-by-one error that causes the location icon to stay on

Commit bdfde4fc820fad768dbc596b17507e4cdc84b850 added Bluetooth AppOps
capabilities, but it contained a subtle bug where the string representation
was added in the wrong place, offseting every operation after it by 1. This
broke the toString functionality but didn't have any consequence since this
was used for logging purposes only.

Commit b01b08928a42a626f5f1c6c18a20d786fb873d75 changed AppOps so that
operations are persisted by name instead of by index, this caused the string
representation offset to affect functionality and, among other things, one
of the consequences was that coarse location requests were being interpreted
by AppOps as high-energy location requests.

Change-Id: I319f1ac1c5910098689b4cb8645eb92c0e3538cb
telephony: SignalStrengh: Don't calculate a LTE snr if the srq is invalid

If the previous values are invalid and signal quality is -1, chances are there's
no LTE signal at all, so don't calculate the SNR and mark it invalid as well.

This fixes the strength indicator in GSM devices where it was being skewed
by the ghost LTE value

Change-Id: I070573401c141aa99941a332ee256246697abb90