Upgrade Karaf base images to version 2.1
<!-- ======================================================= -->
<!-- === Karaf base image versions for docker, s2i (istag == s2i) -->
<!-- Upstream -->
- <version.image.karaf.upstream.docker>2.0</version.image.karaf.upstream.docker>
+ <version.image.karaf.upstream.docker>2.1</version.image.karaf.upstream.docker>
<version.image.karaf.upstream.s2i>${version.image.karaf.upstream.docker}</version.image.karaf.upstream.s2i>
<!-- RedHat -->
