[ppc64le] fix notary vendor link

Notary switched to vendor a while ago, so make that change here. Change
is consistent with all other dockerfiles.

Signed-off-by: Christopher Jones <tophj@linux.vnet.ibm.com>

Dockerfile.ppc64le

@@ -136,9 +136,9 @@ RUN set -x \
 	&& export GOPATH="$(mktemp -d)" \
 	&& git clone https://github.com/docker/notary.git "$GOPATH/src/github.com/docker/notary" \
 	&& (cd "$GOPATH/src/github.com/docker/notary" && git checkout -q "$NOTARY_VERSION") \
-	&& GOPATH="$GOPATH/src/github.com/docker/notary/Godeps/_workspace:$GOPATH" \
+	&& GOPATH="$GOPATH/src/github.com/docker/notary/vendor:$GOPATH" \
 		go build -o /usr/local/bin/notary-server github.com/docker/notary/cmd/notary-server \
-	&& GOPATH="$GOPATH/src/github.com/docker/notary/Godeps/_workspace:$GOPATH" \
+	&& GOPATH="$GOPATH/src/github.com/docker/notary/vendor:$GOPATH" \
 		go build -o /usr/local/bin/notary github.com/docker/notary/cmd/notary \
 	&& rm -rf "$GOPATH"