(svn r2886) Rename the "owner" attribute to "m1", because when it stores an owner it is accessed by [GS]etOwner anyway and when it doesn't store an owner, but arbitrary data, accessing a field called "owner" is confusing.

disaster_cmd.c

@@ -337,7 +337,7 @@ static void DestructIndustry(Industry *i)
 
 	for (tile = 0; tile != MapSize(); tile++) {
 		if (IsTileType(tile, MP_INDUSTRY) && _m[tile].m2 == i->index) {
-			_m[tile].owner = 0;
+			_m[tile].m1 = 0;
 			MarkTileDirtyByTile(tile);
 		}
 	}