When -j is specified ignore the path to the source file and just
zip it with its filename. -j overrides -C, and -C overrides -j,
so -j -f path1 -C dir -f path2 will junk the path for path1, but
treat path2 as relative to dir.
Remove the filepath.Clean for the FileArgs, it would convert ""
to "." sometimes, and everything gets cleaned in zip already for
the non-command-line use cases.
Test: m checkbuild
Change-Id: I7d90572c622ee0c6f35967ff31d067b5312c72eb
b7c6911dd1