Make sure that any changes to the boot animation can be picked up
and rebuilt by running 'mka bootanimation.zip'.
Change-Id: Ice10e919df4c1b651c5c5dbb9700cab38eeac748
(cherry picked from commit e796a286bd72df3e4715164171a3e7ef6d2eadb2)
For some reason the mkdir command:
mkdir -p $ANDROID_PRODUCT_OUT/obj/BOOTANIMATION/bootanimation/part{0..2}
creates a directory part{0..2} instead of three separate directories.
Non-fatal build errors and a 386 byte bootanimation.zip file result.
This explicitly creates each directory.
Change-Id: Ia6ae0e4f64521992de8cc34a376af3eaac5c8819
