Drop dead code from sun.net.www

This covers:
  - HeaderParser.java
  - protocol.jar.URLJarFileCallback and URLJarFile.setCallBack()

Bug: 29569605
Test: Nothing at this CL; "make droid cts checkbuild"
      and libcore tests at follow-up CL built on top of this one
      that will get merged at the same time.

Change-Id: Id8e065d80d010a96a93ec3cb562da6ff586cc02e