SLING-3647 - No repository found at ... URL scheme http not supported.
only

Try and load the DAVExRepositoryFactory early on, so that it's available
when needed by the RepositoryProvider.

I am not 100% sure of the underlying cause, but it seems to be some
unfortunate interaction between the ServiceLoader mechanism and OSGi
classloading.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1602363 13f79535-47bb-0310-9956-ffa450edef68