autotest: Update soaring test for THERMAL mode.

Tools/autotest/arduplane.py

@@ -1755,7 +1755,7 @@ class AutoTestPlane(AutoTest):
 
         # Wait to detect thermal
         self.progress("Waiting for thermal")
-        self.wait_mode(24,timeout=600)
+        self.wait_mode('THERMAL',timeout=600)
 
         # Wait to climb to SOAR_ALT_MAX
         self.progress("Waiting for climb to max altitude")
@@ -1822,7 +1822,7 @@ class AutoTestPlane(AutoTest):
         # Make sure this causes throttle down.
         self.wait_servo_channel_value(3, 1200, timeout=2, comparator=operator.lt)
 
-        self.progress("Waiting for next WP with no loiter")
+        self.progress("Waiting for next WP with no thermalling")
         self.wait_waypoint(4,4,timeout=1200,max_dist=120)
 
         # Disarm