Do not bundle META-INF in configuration

This fixes a packaging issue, where the META-INF directory of
downstream configuration jars would be included in final distribution's
configuration directory -- e.g. we had a useless configuration/META-INF
directory.

Should be included in stable branch, too.

Change-Id: I96ad12589876d2585dab5cd3ddee4e271fbb3231
Signed-off-by: Robert Varga <rovarga@cisco.com>