Update glue/gonk/external/qemu

[Jonathan Griffin]

Currently, glue/gonk/external/qemu points to the tools_r13 branch of that repo. However, there's a change in the master branch which we need in order to be able to test vibrator and other API's in the emulator; that change is joneschrisg/android-external-qemu@2d88523.

Can we update glue/gonk/external/qemu to point to this commit?

[Chris Jones]

Have you confirmed that our testing code works fine with the version of the code on the master branch?

CC @shianyow

[Jonathan Griffin]

@cgjones @shianyow yes, all of the tests that pass with the current branch also pass with the master branch

[Chris Jones]

8e8dacd