Fix a problem in mod_mime_magic where file descriptor 2 would be

Fix a problem in mod_mime_magic where file descriptor 2 would be
inadvertently closed.  This logic was in the uncompress child in 1.3
but was in the parent in 2.0.

uncompress_child() was renamed to create_uncompress_child() to reflect
a change in use since 1.3.

A note was added about missing 1.3 logic for doing something with the
stderr of the uncompress process.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88538 13f79535-47bb-0310-9956-ffa450edef68