[PATCH] Uninstall configuration files

Hello,

     Please review the attached patch. The patched Makefiles delete
installed configuration files, restoring functionality removed from
Squid some time ago, but hopefully in a safer manner. This is the
cleanest way I could find to make "make distcheck" work again (with the
other pending SourceLayout changes).

-------- change log ------------------
Made "make distuninstallcheck" work:

Fixed "make distuninstallcheck" by removing installed configuration
files iff they are identical to the installed default configuration files.

Added scripts/remove-cfg.sh to do the safe removal because we need that
functionality in many Makefiles.

Made installed mime.conf removal safe. We were removing it without
checking for modifications.

Added commands to remove the following installed default configuration
files: cachemgr.conf.default and msntauth.conf.default.
--------------------------------------------

Thank you,

Alex.
bb:approve