CMakeLists.txt: Update header install list

Change-Id: I8b2f99a036ee9885f2a47aa7d5026e060a31ed05
Reviewed-on: http://review.couchbase.org/36395
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>