RequestInitDocument 404 friendly reminder

Summary: 404  don't friendly reminder when RequestInitDocument   file don't exsists,we can't quickly positioning problem,so modify this function friendly reminder.
Closes https://github.com/facebook/hhvm/pull/4494

Reviewed By: @sgolemon

Differential Revision: D1753403

Signature: t1:1753403:1419556980:e34cd738458fe8ae92773e468cf1b48bb636382d
look in /usr/lib64 in FindGLIB.cmake

Summary: glib won't be found on fedora/centos without it.
Closes https://github.com/facebook/hhvm/pull/4522

Reviewed By: @sgolemon

Differential Revision: D1757717

Signature: t1:1757717:1419556976:9f53a117ef8d625abd48f3358fbff25dd9f78ca8
Implement Memcached::quit

Summary: Closes #4455
Closes https://github.com/facebook/hhvm/pull/4473

Reviewed By: @sgolemon

Differential Revision: D1743479

Signature: t1:1743479:1419557100:f12b5a03590b672bdccf4f19196bd4ca24eca321