Prevent a possible impossible when guard relocated a monster

doc/fixes36.3

@@ -136,6 +136,7 @@ have 'O' update persistent inventory window if 'implicit_uncursed',
 when spellcasting monster aimed at wrong spot due to not being able to see
 	invisible hero, feedback could be erroneous if hero could see self
 	[messages used 'if (Invisible)' test where 'if (Invis)' was meant]
+prevent impossible when guard tries to relocate a monster on a full level
 
 
 Fixes to Post-3.6.2 Problems that Were Exposed Via git Repository

src/vault.c

@@ -79,7 +79,8 @@ boolean forceshow;
             } else if (!in_fcorridor(grd, u.ux, u.uy)) {
                 if (mtmp->mtame)
                     yelp(mtmp);
-                (void) rloc(mtmp, FALSE);
+                if (!rloc(mtmp, TRUE))
+                    m_into_limbo(mtmp);
             }
         }
         lev = &levl[fcx][fcy];