Add ftp-archive method for old releases

Ticket:		[6572440546]
Submitted by:	jbeich@tormail.org
jail.sh: consistently accept svn revision number

Currently, certain branches allow specifying revision number for svn
checkout due to how sh(1) treats excluding glob patterns: ![0-9] vs. [^0-9].
The behavior is actually useful for debugging a port against a fixed bug
in userland to compare "before" and "after" or to check for a regression.
"allbsd" method is just not atomic enough and may be unavailable do to
broken build, hosting issues, etc.

Ticket:		[8526dcecaf]
Submitted by:	jbeich@tormail.org