Remove unused shared libs from otatools.

libcurl-host.so was added for delta_generator (commit f8e6fbe2).
libext2_misc.so and libext2_profile-host.so were added for e2fsck and
build_verity_tree (commit d0ec6657). None of them is actively used by
otatools.

Bug: 34738751
Test: `m -j otatools-package`. Unzip and check that there's no missing
      shared libs reported by ldd.
Change-Id: Id229e450f5f2eaa03a6c6cf568a1912add06754c