r.fill.dir: Fix Resource Leak Issue in dopolys.c and filldir.c (OSGeo#6358)

* Fix Resource Leak Issue

* Update raster/r.fill.dir/dopolys.c

Author: ShubhamDesai

raster/r.fill.dir/dopolys.c

@@ -71,9 +71,11 @@ int dopolys(int fd, int fm, int nl, int ns)
             }
         }
     }
-    if (found == 0)
+    if (found == 0) {
+        G_free(cells);
+        G_free(dir);
         return 0;
-
+    }
     /* Loop through the list, assigning polygon numbers to unassigned entries
        and carrying the same assignment over to adjacent cells.  Repeat
        recursively */

raster/r.fill.dir/filldir.c

@@ -39,14 +39,12 @@ void check(CELL newdir, CELL *dir, void *center, void *edge, double cnst,
 int fill_row(int nl UNUSED, int ns, struct band3 *bnd)
 {
     int j, offset, inc, rc;
-    void *min;
+    char *min;
     char *center;
     char *edge;
 
     inc = bpe();
 
-    min = G_malloc(bpe());
-
     rc = 0;
     for (j = 1; j < ns - 1; j += 1) {
         offset = j * bpe();