This reverts commit 78c7bbc3.

It is no longer the case that both expat_utf8 and expat_utf16 are linked
into the same library: we only use expat_utf16 in shell Explorer
extensions, which cannot be linked into libmerged anyway.

Conflicts:
	expat/expat-2.1.0.patch

Change-Id: I579c10d405d8a40cafcb2dbe09e967c6079f7b16