repack_bootimg: Support using local files as repack source

Bug: 202129499
Test: repack_bootimg --local --dst_bootimg boot.img --ramdisk_add OWNERS
Test: repack_bootimg --local --dst_bootimg boot.img --ramdisk_add $(pwd)/OWNERS:OWNERS
Test: (should fail) repack_bootimg --local --dst_bootimg boot.img --ramdisk_add $(pwd)/OWNERS
Change-Id: I4afc676ebb169c909fce9c00189ef6f8cc46be7f
1 file changed