Remove useless p2.inf file in o.e.jdt.launching.ui.macosx

It was introduced via
de87173
most likely to workaround org.eclipse.swt host not mandating dependency
on the correct os/arch specific fragment. As SWT does that this is
useless and just generates issues with maven publishing.
Pointed out in
eclipse-platform/eclipse.platform.releng.aggregator#3264 (comment)

Author: akurtakov