cmake: fix build in separate directory
cmake: fix build in separate directory

git-version.sh cannot be found when cmake is configured in a different
build dir.

Signed-off-by: Jiri Slaby <3a42a5d4389f053b0ed9c8486a7a83f2a41a9eea@fi.muni.cz>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg