This move avoids that all consumers of org.eclipse.jgit depend on Apache
httpclient. Also add another feature to make this optional for OSGi
consumers as well.
Change-Id: I5ef5e00c53678b9e1d7cfd54bbca3ff6f1c1c967
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>