Back out ap_set_default_perms(). Remove old logic to play with umask

Back out ap_set_default_perms().  Remove old logic to play with umask
around the creation of the httpd.pid file.  Pass explicit permissions to
ap_open(), omitting write-ability except by the owning user.  As always,
we end up with rw-r--r-- for the permissions unless the umask is something
unusual.

Note that the OS/2 and Win32 implementations of ap_open() ignore the
permissions parameter altogether.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85550 13f79535-47bb-0310-9956-ffa450edef68