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
Avoid overwriting EGL14.EGL_NO_SURFACE

(This is an update after the generator update.)

Both EGL14 and EGLExt have the same initialization codes for
EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_CONTEXT and EGL14.EGL_NO_DISPLAY.
Since EGLExt is initialized later, they are overwritten by EGLExt's
initialization codes.
Therefore, EGL_NO_SURFACE returned by methods in EGL14 is not
actually EGL14.EGL_NO_SURFACE object and it makes several problems in
handling error cases.
For instance, "Let's fish" game application cannot be run on L.

To solve the problem, this patch makes EGL14.EGL_NO_SURFACE,
EGL14.EGL_NO_CONTEXT and EGL14.EGL_NO_DISPLAY initialized just once.

Change-Id: Icce878164ff0b715ad2b5a2cd038a9616c7cf1e9
Avoid overwriting SYSTEM_ADJ with PERSISTENT_PROC_ADJ

If an application running on system_process has a persistent flag,
the oom_adj value for system_process is unexpectedly overwritten
to PERSISTENT_PROC_ADJ (-12).

We must keep SYSTEM_ADJ (-16) for system_process.
This change guards against overwriting SYSTEM_ADJ with
PERSISTENT_PROC_ADJ

Change-Id: I8f334d93b82271f9a0cfbbef34a75af2dacb186b