Remove ap_destroy_context from Apache 2.0. With the name change back to

ap_pool_t, this function doesn't make sense.  This also changes all
references to ap_destroy_context back to ap_destroy_pool.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85271 13f79535-47bb-0310-9956-ffa450edef68