gcc_release (BRANCH): Rename to...

	* gcc_release (BRANCH): Rename to...
	(CVSBRANCH): ...new macro, and use BRANCH for the variant users
	will see.
	(FTP_BRANCH): For snapshots, include ${BRANCH} in the last part
	of the directory name.
	Use .snapshot_date-${BRANCH} instead of .snapshot_date.

From-SVN: r68777