Fix (or rather workaround) the bug which caused second reading

of graphviz file to fail. Looks like the parser is not reenterant.

Patch from anynymous user.


[SVN r21951]

libs/graph

@@ -1 +1 @@
-Subproject commit 547cd77748eb24e0220b2e2cfb1bcb6bc691740b
+Subproject commit a11e93caa44f6690fea3901445f30375c51da12b