Upgrade libxml to 2.9.1

Bug: 7246045

Change-Id: I8d0abc6b9e3f691f6e282a8912d1af7b24b21aa5
am 9a32acf9: Merge "Remove warnings from this lib, should look at fixing them."

* commit '9a32acf96297867a17e26b44c86604823d24c164':
  Remove warnings from this lib, should look at fixing them.
am ea22b769: Merge "Do not disable warning not supported by Gcc 4.2.1"

* commit 'ea22b769c74393d832eb047b131a70087b022a45':
  Do not disable warning not supported by Gcc 4.2.1
Disable warning spam

Disable warnings from libxml2 library. Also instruct gcc not to
exit when warning options are not supported.

Change-Id: I4c697ab006fa4978a829abe73a7215dbc126ae17
Revert "Disable warning spam"

This reverts commit e4de1ec774fda5c65697f08621ebcf27f0ad2c2e.

Change-Id: I87524109954496c5a1c3437f2864c73bcac39896
libxml2: Include XML validation in the build

Change-Id: Ic81493e883fdcb11a7e8507b6216df545514e3a5
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
am ba9ec441: Merge "Activate the "XInclude" feature by default"

* commit 'ba9ec441bf16e801106029292e6e51a7909373b6':
  Activate the "XInclude" feature by default
am 399e808f: Merge "Switch libxml2 to the new icu."

* commit '399e808f940777d18efe377bd34f738dc84729e0':
  Switch libxml2 to the new icu.
resolved conflicts for merge of c6af5d96 to stage-aosp-master

Change-Id: Ibcfd252cdb36bfd822cc782fcabb6041ed9a06a3
resolved conflicts for merge of 4b31d61a to stage-aosp-master

Change-Id: I2da23f2df8a23e00a1f9bd26e276a2fffe12cfdb
resolved conflicts for merge of 827d13e4 to stage-aosp-master

Change-Id: Ibeccd4d5b0b511b7a3e4c2a6c1b7b8469f3d699f
am c6a17b00: Merge "Don\'t .gitignore xmlversion.h and check it in."

* commit 'c6a17b00501f847702d20320ba95d12c07ccc9e8':
  Don't .gitignore xmlversion.h and check it in.
am bd7379f5: Merge "Actually check in xmlversion.h!"

* commit 'bd7379f5dc691a177b8e3bf3b765e8388bf06b4c':
  Actually check in xmlversion.h!
am 043d2394: Merge "Disable ftp, http, and zlib in the source."

* commit '043d23940bbf2cce10d302d5cb54a9e1e82a71f8':
  Disable ftp, http, and zlib in the source.
am 8cca2fc3: Merge "HAVE_ZLIB_H wrongly overrides LIBXML_ZLIB_ENABLED."

* commit '8cca2fc34d04fa6eb75f019270696665785a3c8a':
  HAVE_ZLIB_H wrongly overrides LIBXML_ZLIB_ENABLED.