common: add quotes to satisfy kati/bash/make/whatever

* Honestly, I have no idea why this works. Or, to put it more
  precisely, why it works without this on _some_ devices and not
  others. All of a sudden?

* Without this patch I'm getting:
    /opt/out/14.1/build-cm_d2vzw-clobber.ninja is missing, regenerating...
    terminate called after throwing an instance of 'std::out_of_range'
      what():  basic_string::erase
    make: *** [build/core/ninja.mk:167: /opt/out/14.1/build-cm_d2vzw-clobber.ninja] Aborted (core dumped)

    #### make failed to build some targets (5 seconds) ####

Change-Id: I4bf43868bf7dfe13df57151ae3597246164cbebc