Test for error status of shl_findsym. Fixes #505417. 2.2.1 candiate.

Misc/ACKS

@@ -160,6 +160,7 @@ Jonathan Giddy
 Chris Gonnerman
 David Goodger
 Hans de Graaff
+Eddy De Greef
 Duncan Grisby
 Dag Gruneau
 Michael Guravage

Python/dynload_hpux.c

@@ -47,7 +47,10 @@ dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
 	PyOS_snprintf(funcname, sizeof(funcname), FUNCNAME_PATTERN, shortname);
 	if (Py_VerboseFlag)
 		printf("shl_findsym %s\n", funcname);
-	shl_findsym(&lib, funcname, TYPE_UNDEFINED, (void *) &p);
+	if (shl_findsym(&lib, funcname, TYPE_UNDEFINED, (void *) &p) == -1) {
+		shl_unload(lib);
+		p = NULL;
+	}
 	if (p == NULL && Py_VerboseFlag)
 		perror(funcname);