Revert "Recognize --head as an alias for --HEAD"

This reverts commit c32ab0a35a2dfa9b593f759ef0ae8b7af077b0b7.

There are other hard-coded uses of HEAD, in build_options for instance.
These all need to be fixed before enabling this.
subversion: use serf 1.3.4

Closes #26612.
avfs 1.0.1

Closes #25502.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
archivemount 0.8.3

Closes #25501.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
ical-buddy: fix audit
rdfind: fix test

Closes #26649.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>