Remove broken -sha1 option from server_cert_fingerprint (#1249)

Remove broken -sha1 option from server_cert_fingerprint (#1249)

server_cert_fingerprint support for the sha1 parameter has been broken
for years, probably since its inception (2012 commit 42d3334). The bug
was known since at least 2018 when it was mentioned in Bug 4847
discussion.  The single-dash syntax violates the double-dash pattern
used for other --long ACL options. If fixed, using the option would not
change Squid behavior because SHA1 is the default (and the only
supported) fingerprinting algorithm.

The option was meant to allow admins to be explicit about that default
in case it changes in the future, but implementation bugs derailed that
plan. The fix is not straightforward, and we should be focusing on more
important things.