Fix 'make all' for other platforms
Since commit d7e2c4ce7 ("Use gometalinter for linting") command
"make all" fails on all the non-default platforms (i.e. ARMs, PPC, and
s390) in this way:
# make all
...
Congratulations! All commits are properly signed with the DCO!
/go/src/github.com/docker/docker/hack/validate/gometalinter: line 6: gometalinter: command not found
Makefile:105: recipe for target 'all' failed
make: *** [all] Error 127
Make sure gometalinter is installed for those platforms
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>