Finds correct property to set fan speed

Fixes openbmc/openbmc#1563

Change-Id: I73ce61e0416318917902ffdf4969b600236772d9
Signed-off-by: Leonel Gonzalez <lgonzalez@us.ibm.com>
diff --git a/module/obmc/wsgi/apps/rest_dbus.py b/module/obmc/wsgi/apps/rest_dbus.py
index 55d5b44..c51e4f9 100644
--- a/module/obmc/wsgi/apps/rest_dbus.py
+++ b/module/obmc/wsgi/apps/rest_dbus.py
@@ -333,10 +333,11 @@
             properties = self.try_properties_interface(iface.GetAll, i)
             if not properties:
                 continue
-            prop = obmc.utils.misc.find_case_insensitive(
+            match = obmc.utils.misc.find_case_insensitive(
                 prop, properties.keys())
-            if prop is None:
+            if match is None:
                 continue
+            prop = match
             return prop, i