Removing the sloeber update sites

As you install from the update site there is no need for the update
sites to be here. Moreover I think it is causing issues with packages
not found.

Author: jantje

io.sloeber.updatesite/category.xml

@@ -97,7 +97,5 @@
    </category-def>
    <category-def name="Dependencies" label="Dependencies (will be automatically installed when needed)"/>
    <repository-reference location="http://download.eclipse.org/releases/photon" enabled="true" />
-   <repository-reference location="http://eclipse.baeyens.it/update/V4/nightly" enabled="false" />
-   <repository-reference location="http://eclipse.baeyens.it/update/V4/stable" enabled="true" />
    <repository-reference location="http://build.eclipse.org/technology/babel/update-site/I20180721-0600/photon/" enabled="true" />
 </site>