Drop Release label in favor of OSBS release_bump plugin.

OSBS can automatically bump the release number, for that
we just need to drop the label from the Dockerfile

See https://pagure.io/ContainerSIG/container-sig/issue/1

Signed-off-by: Clement Verna <cverna@tutanota.com>

Dockerfile

@@ -1,10 +1,9 @@
-FROM registry.fedoraproject.org/fedora:rawhide
+FROM registry.fedoraproject.org/fedora:29
 
-ENV VERSION=0 RELEASE=1 ARCH=x86_64
+ENV VERSION=0 ARCH=x86_64
 LABEL com.redhat.component="docker" \
       name="docker" \
       version="$VERSION" \
-      release="$RELEASE.$DISTTAG" \
       architecture="$ARCH" \
       usage="atomic install --system --system-package=no docker && systemctl start docker" \
       summary="The docker daemon as a system container." \