image.mk: keep underscores when sanitize PROFILE
Underscores don't harm in filenames, however the sanitize function from
version.mk replaces them, causing inconsistent filenames.
A fix tried to solve this previously via
dfe99645dbdd4460f394beaa3a05091cd40b5942 however I did not look close
enough:
openwrt-ath79-generic-8dev-carambola2.manifest # current
openwrt-ath79-generic_8dev-carambola2.manifest # patched
---------------------^
Eventually the sanitization of PROFILES *could* be removed as more and
more profiles follow the device tree approach of vendor_model, neither
containing upper case letters nor spaces.
Signed-off-by: Paul Spooren <[email protected]>
Paul Spooren