s/controla/controlla/g

Change-Id: I03c0f320181b969edb271cded8a80dcebd12334e
diff --git a/y2015/control_loops/python/elevator.py b/y2015/control_loops/python/elevator.py
index 89e16cd..464011b 100755
--- a/y2015/control_loops/python/elevator.py
+++ b/y2015/control_loops/python/elevator.py
@@ -77,9 +77,9 @@
 
     print self.A
 
-    controlability = controls.ctrb(self.A, self.B)
-    print "Rank of augmented controlability matrix.", numpy.linalg.matrix_rank(
-        controlability)
+    controllability = controls.ctrb(self.A, self.B)
+    print "Rank of augmented controllability matrix.", numpy.linalg.matrix_rank(
+        controllability)
 
     q_pos = 0.02
     q_vel = 0.400