Finish issue #3479 - mime.types extension matching case sensitive
Finish issue #3479 - mime.types extension matching case sensitive

When I added the feature that allows you to specify a MIME mapping
file in your runtime configuration (for use when doing automatic
property setting on 'add' and 'import'), I failed to recall that those
mappings are meant to be interpreted case-insensitively.  This commit
remedies that.

* subversion/libsvn_subr/io.c
  (file_ext_tolower): New function, copied wholesale from
    libsvn_subr/config.c:make_hash_key().
  (svn_io_parse_mimetypes_file): Use file_ext_tolower() to ensure that
    the keys in the MIME mappings hash are lower-cased.
  (svn_io_detect_mimetype2): Use file_ext_tolower() to normalize the
    extension of the filename we're detecting MIME types for to
    lowercase so it has a better chance of matching items in the MIME
    mapping hash.  While here, avoid testing for file existence until
    *after* we fail at name-based MIME association.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion