Remove explicit plugin version numbers in feature.xml

The build fills them in automatically.

org.eventb.texteditor.feature/feature.xml

@@ -202,21 +202,21 @@ Inc. in the United States, other countries, or both.
          id="org.eventb.texteditor.ui"
          download-size="0"
          install-size="0"
-         version="3.4.1.qualifier"
+         version="0.0.0"
          unpack="false"/>
 
    <plugin
          id="org.eventb.texttools"
          download-size="0"
          install-size="0"
-         version="3.4.1.qualifier"
+         version="0.0.0"
          unpack="false"/>
 
    <plugin
          id="org.eventb.texteditor.parsers"
          download-size="0"
          install-size="0"
-         version="3.4.1.qualifier"
+         version="0.0.0"
          unpack="false"/>
 
 </feature>