Correction of the 2nd example in 'interplevel' docstring

Author: pgamez

src/wrf/interp.py

@@ -90,7 +90,7 @@ def interplevel(field3d, vert, desiredlev, missing=default_fill(np.float64),
             wrfin = Dataset("wrfout_d02_2010-06-13_21:00:00")
 
             rh = getvar(wrfin, "rh")
-            z = getvar(wrfin, "z")
+            z = getvar(wrfin, "z", msl=False)
             pblh = getvar(wrfin, "PBLH")
 
             rh_pblh = interplevel(rh, z, pblh)