Add *.rc to shebangfix whitelist

[AMDmi3]

Summary

There are #!/bin/rc files installed by e.g. go:

Error: '/bin/rc' is an invalid shebang you need USES=shebangfix for 'go/src/all.rc'
Error: '/bin/rc' is an invalid shebang you need USES=shebangfix for 'go/src/clean.rc'
Error: '/bin/rc' is an invalid shebang you need USES=shebangfix for 'go/src/make.rc'
Error: '/bin/rc' is an invalid shebang you need USES=shebangfix for 'go/src/run.rc'

I'm not sure if these are usable on FreeBSD at all. We could add a shebangfix for them to use ${LOCALBASE}/bin/rc or whitelist them in qa.sh, and for now let's go the latter way.

[mat]

We don't seem to have a bin/rc in our go ports, so, yeah, go ahead.

[rene]

There is no /bin/rc, so the warning is correct, or am I missing something?

[mat]

I wonder if, instead, bin/rc should not be whitelisted.

[AMDmi3]

Agreed with mat@ suggestion, whitelist /bin/rc instead

[mat]

After committing this, please unfix lang/go14 :-)

[ak]

Because of name collision, that change masks potential shebang error in devel/plan9port which depends on shells/rc (plan9-like shell) which provides bin/rc.
It's one obscure port, so I guess that change is ok, but it would be nice to at least add comment about this potential issue.