Fix generation of eclipse project

When generating eclipse project using bucklets/tools/eclipse.py, the
source folders were not generated.

Change-Id: Ib50d37c12fb3cb750d124e9aef8ba8528ede6873
diff --git a/tools/eclipse.py b/tools/eclipse.py
index f5b46f8..7866c78 100755
--- a/tools/eclipse.py
+++ b/tools/eclipse.py
@@ -87,7 +87,7 @@
   src = set()
   lib = set()
 
-  java_library = re.compile(r'[^/]+/gen/(.*)/lib__[^/]+__output/[^/]+[.]jar$')
+  java_library = re.compile(r'[^/]+/gen(.*)/lib__[^/]+__output/[^/]+[.]jar$')
   for p in query_classpath(MAIN):
     m = java_library.match(p)
     if m: