Don't discard directory entries in jar files.

This is a structural change, and breaks code that looks up
directory resource names (icu4j for example).

This change also includes a minor cosmetic change to use a
while() loop instead of for(;;).

bug: 19108324
Change-Id: Ib12c3c1d55f14a089702e5e668d7a704f298e1f4
1 file changed