Merge changes I70c94c4b,Ifd8769ed am: 11d18f1491
am: 974da4b603

* commit '974da4b60389719677d04f71c1e6568f6d687139':
  adb: make mkdirs/secure_mkdirs do what they say.
  adb: remove use of mkdirs from `adb backup`.