Fix Eclipse project generation

Since Ibecff463d5, generation of Eclipse project was broken, i.e., the
source folders were not included. The Buck version used in that commit
requires classpaths to be absolute.

Change-Id: I786e3424c29d315d2ade5485be56490dcd93a26d
diff --git a/tools/eclipse.py b/tools/eclipse.py
index 25fe28c..3a54b7c 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$')
+  java_library = re.compile('.*/buck-out/gen(.*)/lib__[^/]+__output/[^/]+[.]jar$')
   for p in _query_classpath(MAIN):
     m = java_library.match(p)
     if m: