RawDecoder: decodeMetaData(), checkSupport(): drop wrong return keyword.
RawDecoder: decodeMetaData(), checkSupport(): drop wrong return keyword.

darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed