Compute the needed shared libs for otatools.

This keeps the packed shared libs in sync with their executables.

This CL also changes the packing location of mke2fs.conf, from
system/extras/ext4_utils/mke2fs.conf to bin/mke2fs.conf.

Bug: 34738751
Test: `m -j otatools-package`. Compare the packed files against the ones
      prior to this CL.
Change-Id: Icae88e3cd898460f5ba7dc11ab8a57350630c432