fix grid bug travel bug

From a bug report, grid bug could travel 1 step diagonally
due to special case code in findtravelpath that did not check grid bug
movement restriction

doc/fixes34.4

@@ -392,6 +392,7 @@ writing while blind no longer possible for books, might fail for scrolls
 blanking items in pools while blind shouldn't reveal new obj description
 	for ones which had been seen before becoming blind
 avoid infinite loop in topten output when killed by long-named monster
+grid bug could move diagonally 1 step using travel command
 
 
 Platform- and/or Interface-Specific Fixes

src/hack.c

@@ -789,7 +789,8 @@ findtravelpath(guess)
 boolean guess;
 {
     /* if travel to adjacent, reachable location, use normal movement rules */
-    if (!guess && context.travel1 && distmin(u.ux, u.uy, u.tx, u.ty) == 1) {
+    if (!guess && context.travel1 && distmin(u.ux, u.uy, u.tx, u.ty) == 1 &&
+	!(u.ux != u.tx && u.uy != u.ty && NODIAG(u.umonnum))) {
 	context.run = 0;
 	if (test_move(u.ux, u.uy, u.tx-u.ux, u.ty-u.uy, TEST_MOVE)) {
 	    u.dx = u.tx-u.ux;