Selectors depof: rdepof: subportof: ignore -p

[ryandesign (Ryan Carsten Schmidt)]

man port says:

       -p
           Despite any errors encountered, proceed to process multiple ports and commands.

Nevertheless, it doesn't seem to do that when using the subportof: selector. For example, this works:

$ port -p info --name asdf zlib
Error: Port asdf not found
name: zlib

But this doesn't:

$ port -p info --name subportof:asdf zlib
Error: process_cmd failed: Port asdf not found

[ryandesign (Ryan Carsten Schmidt)]

Some other selectors have this problem too:

$ port -p info --name depof:asdf zlib
Error: process_cmd failed: Port asdf not found

$ port -p info --name rdepof:asdf zlib
Error: process_cmd failed: Port asdf not found

[jmroot (Joshua Root)]

In 150c99dc127804a45ace99d6d2289a0d98da1cab/macports-base (master):

get_{dep_,sub}ports: don't error if -p was used

Closes: #61015