fix #7414 - bug with Japanese names for Samurai

Description for use when an item hasn't been seen up close yet falls
back to real name if there is no separate description, but was doing
so before real name substitution for samurai.
 actualn = foo;
 dn = description ? description : actualn;
 if (Samurai)
  actualn = bar;
So player saw a flail (via 'dn') until dknown bit got set, then
nunchaku (via 'actualn' after it got set to samurai-specific value).

Wait until after substitution of Japanese real names before falling
back to real name when there's no description.

src/objnam.c

@@ -403,7 +403,7 @@ unsigned cxn_flags; /* bitmask of CXN_xxx values */
     register struct objclass *ocl = &objects[typ];
     int nn = ocl->oc_name_known, omndx = obj->corpsenm;
     const char *actualn = OBJ_NAME(*ocl);
-    const char *dn = OBJ_DESCR(*ocl) ? OBJ_DESCR(*ocl) : actualn;
+    const char *dn = OBJ_DESCR(*ocl);
     const char *un = ocl->oc_uname;
     boolean pluralize = (obj->quan != 1L) && !(cxn_flags & CXN_SINGULAR);
     boolean known, dknown, bknown;
@@ -411,6 +411,10 @@ unsigned cxn_flags; /* bitmask of CXN_xxx values */
     buf = nextobuf() + PREFIX; /* leave room for "17 -3 " */
     if (Role_if(PM_SAMURAI) && Japanese_item_name(typ))
         actualn = Japanese_item_name(typ);
+    /* 3.6.2: this used to be part of 'dn's initialization, but it
+       needs to come after possibly overriding 'actualn' */
+    if (!dn)
+        dn = actualn;
 
     buf[0] = '\0';
     /*