ndk-gdb: More robust error detection for 'adb shell' commands.

This allows ndk-gdb to properly detects when some adb shell commands fail.
This prevents certain errors from incorrectly propagating to later parts
of the script.

See http://code.google.com/p/android/issues/detail?id=14002 for context.

Change-Id: I49e22e397bad5d39a9f002aa41f029d798038254
3 files changed