Fix Typo in vvp's scope search in interactive mode.

When vvp parses a command which it thinks is a system call it tries to
match the symbols to values in the scope. The typo uses the wrong index
variable to access the vpi table. This results in a failed dynamic cast
which goes unchecked until the value is dereferenced, resulting in a
segfault.

vvp/stop.cc

@@ -138,7 +138,7 @@ static void cmd_call(unsigned argc, char*argv[])
 		      case vpiTask:
 		      case vpiNamedBegin:
 		      case vpiNamedFork:
-			scope = dynamic_cast<__vpiScope*>(table[idx]);
+			scope = dynamic_cast<__vpiScope*>(table[tmp]);
 			if (strcmp(scope->scope_name(), argv[idx+1]) == 0)
 			      handle = table[tmp];
 			break;