Strip leading / from source paths in classpath

In Gitiles, buck audit classpath returns entries like:
  buck-out/gen/gitiles-servlet/lib__servlet__output/servlet.jar

Prior to this change, matching the provided regex results in a group
like:
  /gitiles-servlet

We then check for the existence of '/gitiles-servlet/src/main' et
al., which of course fails since this looks like an absolute path.

This regex previously didn't capture the leading '/', but was changed
to do so in Ib50d37c1. Now that it does, we need to strip that before
doing any path existence checks.

Change-Id: I3bd95c1c63db56a5392c3ab56e9715cfc5c7b6a3

tools/eclipse.py

diff --git a/tools/eclipse.py b/tools/eclipse.py
index 7866c78..502d234 100755
--- a/tools/eclipse.py
+++ b/tools/eclipse.py
@@ -91,7 +91,7 @@
   for p in query_classpath(MAIN):
     m = java_library.match(p)
     if m:
-      src.add(m.group(1))
+      src.add(m.group(1).lstrip('/'))
     else:
       lib.add(p)