libstagefright foundation: fix uninitialized varibale warning

gcc-4.9 reports warning for this uninitialized variable
and -Werror make this warning fatal.

Change-Id: I6901362246d53deeded78fa38ad656b167705346
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Merge "libstagefright foundation: fix uninitialized varibale warning"
auto-merger: merge in from aosp/master