fix(bob_genrule) allow '/' in tags
fix(bob_genrule) allow '/' in tags

Change-Id: Ib9a48e1083d0b8382ae1400c17e68701d38ea4fb
Signed-off-by: Brandon Jones <4b9bf0a865bc8cebc86f35fec044585c31220d78@arm.com>

ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build