Fix conflict with coreutils. [1]

Previous in gegl3 the pkgnamesuffix of that port cause gcut to be installed
as gcut3. Now after the move there isn't a pkgnamesuffix anymore. Base the
new suffix on the value off GEGL_VER.

PR: 232054 [1]
Submitted by: tobic@
Reported by: w.schwarzenfeld@utanet.at