Fix error when no closure compiler is around.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@11494 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

build/build.py

@@ -15,7 +15,7 @@ def build(config_file = None, output_file = None, options = None):
     try:
         import closure
         have_compressor.append("closure")
-    except ImportError, E:
+    except Exception, E:
         print "No closure (%s) % E"
     try:
         import closure_ws