v.category: fix https://trac.osgeo.org/grass/changeset/49413 (backport from trunk https://trac.osgeo.org/grass/changeset/69469)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@69471 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.category/main.c

@@ -452,6 +452,8 @@ int main(int argc, char *argv[])
 			    Vect_field_cat_del(Cats, fields[0], Cats->cat[found]);
 			nmodified++;
 		    }
+		    else
+			i++;
 		}
 	    }
 	    Vect_write_line(&Out, type, Points, Cats);