[Eng](6.3.x) Remove the drools-karaf-features for fuse 6.3 in 6.3.x release

There is s drools-karaf-features-6.4.0.Final-redhat-6-features-fuse-6_3.xml included in jboss-brms-bpmsuite-6.3.1-fuse-features.zip.
However as Alessandro pointed the fuse 6.3 isn't released yet. We shouldn't deliver it to customer.
This file should be excluded for bxms 6.3.x releae before fuse 6.3 is GA.