Use tools/currysrc/scripts/repackage-common.sh

The repackage-common.sh script provides support for using the
RepackagingTransform which reduces duplication in project specific
scripts and provides improved support for verifying the transformations
were applied correctly.

Tested by running the srcgen/generate_android_src.sh script and
verifying that it did not change the generated code.

Bug: 117818301
Test: see above
Change-Id: Ib3b0205158b4db1d14e05460575a9268e4538b61