libstagefright: track libziparchive API change.

One last user of the StartIteration ZipString overload...

Bug: http://b/129068177
Test: builds
Change-Id: I6b2619211372b20a721c800452cb7c63105c111e
Merged-In: I723570315285d7c2caadffd71cd2d15efde11819
1 file changed