Fix crash launching qemu on OSX from another location.

It's append only when frozen an you launch the server by hand.

Fix #194

gns3server/modules/qemu/__init__.py

@@ -74,7 +74,11 @@ class Qemu(BaseManager):
             # add specific locations on Mac OS X regardless of what's in $PATH
             paths.extend(["/usr/local/bin", "/opt/local/bin"])
             if hasattr(sys, "frozen"):
+                try:
                     paths.append(os.path.abspath(os.path.join(os.getcwd(), "../../../qemu/bin/")))
+                # If the user run the server by hand from outside
+                except FileNotFoundError:
+                    paths.append(["/Applications/GNS3.app/Contents/Resources/qemu/bin"])
         for path in paths:
             try:
                 for f in os.listdir(path):