ipc: set file permissions on created sockets

When using sockets for IPC the file permissions default to whatever
the umask is.  This isn't a problem on Linux since it uses abstract
namespace sockets which don't have any permissions, but on other
platforms this causes problems with pacemaker which spawns processes
under the hacluster user and ends up failing to connect.

lib/ipc_socket.c

@@ -84,6 +84,9 @@ qb_ipc_dgram_sock_setup(const char *base_name,
 #endif
 	res = bind(request_fd, (struct sockaddr *)&local_address,
 		   sizeof(local_address));
+#if !(defined(QB_LINUX) || defined(QB_CYGWIN))
+	chmod(local_address.sun_path, 0660);
+#endif
 	if (res < 0) {
 		goto error_connect;
 	}