AP_Landing: Fix shadowing with deepstall

Was breaking clang 8 builds

libraries/AP_Landing/AP_Landing_Deepstall.h

@@ -42,17 +42,6 @@ private:
 
     static const struct AP_Param::GroupInfo var_info[];
 
-    // deepstall members
-    enum deepstall_stage {
-        DEEPSTALL_STAGE_FLY_TO_LANDING,    // fly to the deepstall landing point
-        DEEPSTALL_STAGE_ESTIMATE_WIND,     // loiter until we have a decent estimate of the wind for the target altitude
-        DEEPSTALL_STAGE_WAIT_FOR_BREAKOUT, // wait until the aircraft is aligned for the optimal breakout
-        DEEPSTALL_STAGE_FLY_TO_ARC,        // fly to the start of the arc
-        DEEPSTALL_STAGE_ARC,               // fly the arc
-        DEEPSTALL_STAGE_APPROACH,          // fly the approach in, and prepare to deepstall when close 
-        DEEPSTALL_STAGE_LAND,              // the aircraft will stall torwards the ground while targeting a given point
-    };
-
     AP_Float forward_speed;
     AP_Float slope_a;
     AP_Float slope_b;
@@ -69,7 +58,7 @@ private:
     AP_Float min_abort_alt;
     AP_Float aileron_scalar;
     int32_t loiter_sum_cd;         // used for tracking the progress on loitering
-    deepstall_stage stage;
+    DEEPSTALL_STAGE stage;
     Location landing_point;
     Location extended_approach;
     Location breakout_location;