Merge pull request #1050 from blattms/make-wells_equal-work-for-null-wells

Make wells_equal work for null wells.

opm/core/wells/wells.c

@@ -545,6 +545,16 @@ bool
 wells_equal(const struct Wells *W1, const struct Wells *W2 , bool verbose)
 /* ---------------------------------------------------------------------- */
 {
+    // Cater the case where W1 and W2 are the same (null) pointers.
+    if( W1 == W2 )
+    {
+        return true;
+    }
+    if( W1 == NULL || W2 == NULL)
+    {
+        return false;
+    }
+    
     bool are_equal = true;
     are_equal = (W1->number_of_wells == W2->number_of_wells);
     are_equal = are_equal && (W1->number_of_phases == W2->number_of_phases);