Use ::remove instead of std::remove

Change-Id: Idf74ab567acd2034f4251fdfc419ec3abb11e5b3
Reviewed-on: http://review.couchbase.org/31491
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>