Remove SLF4J Plugin from o.e.passage.lic.oshi feature

If a Feature includes a Plugin, it usually includes it with a specific
name and the version that was in the TP when the feature was build.
This prevents consumers from using a slf4j bundle with different
symbolic-name or different version in their TP or product.

This is part of
eclipse-platform/eclipse.platform.releng.aggregator#588

features/org.eclipse.passage.lic.oshi.feature/feature.xml

@@ -36,13 +36,6 @@
       <import feature="org.eclipse.passage.lic.equinox.feature" version="0.0.0"/>
    </requires>
 
-   <plugin
-         id="org.slf4j.api"
-         download-size="0"
-         install-size="0"
-         version="0.0.0"
-         unpack="false"/>
-
    <plugin
          id="com.sun.jna"
          download-size="0"