...to core 906a2e4fa4e9ce231126c608e741c0c0d809157d "Always execute
pack_images.py with the right Python interpreter"
Change-Id: I7c6c9aed33222fb5b902e30a05cefe8f88c66df1
They only depend on the perl script so won't get rebuild if images are
added or removed in source/media/
Use the same hack as in postprocess, make the targets PHONY so they
always get rebuilt.
Also fix a stray \ that caused the wrong output "[PRL] " to be printed
too early.
Change-Id: I03c8696591cf47395211feaed360fbd5642733a0