Fix generated classpath ordering

There is a bug with this script only when plugins are added to the plugins
folder. I found it when attempting to debug the its-bugzilla plugin.
It places the plugin dependent libraries ahead of the Gerrit core libraries
which can cause conflicts and failures with Gerrit core.  This change
switches the ordering.

Change-Id: Id39a9035928c1dcc3daf034f5fdd7d88d87bb024

tools/eclipse/project.py

@@ -138,7 +138,7 @@ def gen_classpath():
         if path.exists(p):
           classpathentry('src', p, out=o)
 
-  for libs in [lib, gwt_lib]:
+  for libs in [gwt_lib, lib]:
     for j in sorted(libs):
       s = None
       if j.endswith('.jar'):