Replace ftp://ftp.funet.fi/pub/mirrors/sources.redhat.com by
ftp://ftp.funet.fi/pub/mirrors/sourceware.org in MASTER_SITE_GCC and
MASTER_SITE_SOURCEWARE, sourceware.org having replaced sources.redhat.com
as the standard name of that host years ago.

This should not bring any practical change for now; it's really the same.