Make *_loop_mt() available in version 3.0 again

The old versions of these symbols were defined with version
tag FUSE_3.0, so this is what we have to use in the .symver
directive.

Author: Nikratio

lib/fuse.c

@@ -4398,7 +4398,7 @@ int fuse_loop_mt_32(struct fuse *f, struct fuse_loop_config *config)
 }
 
 int fuse_loop_mt_31(struct fuse *f, int clone_fd);
-FUSE_SYMVER(".symver fuse_loop_mt_31,fuse_loop_mt@FUSE_3.1");
+FUSE_SYMVER(".symver fuse_loop_mt_31,fuse_loop_mt@FUSE_3.0");
 int fuse_loop_mt_31(struct fuse *f, int clone_fd)
 {
 	struct fuse_loop_config config;

lib/fuse_loop_mt.c

@@ -349,7 +349,7 @@ int fuse_session_loop_mt_32(struct fuse_session *se, struct fuse_loop_config *co
 }
 
 int fuse_session_loop_mt_31(struct fuse_session *se, int clone_fd);
-FUSE_SYMVER(".symver fuse_session_loop_mt_31,fuse_session_loop_mt@FUSE_3.1");
+FUSE_SYMVER(".symver fuse_session_loop_mt_31,fuse_session_loop_mt@FUSE_3.0");
 int fuse_session_loop_mt_31(struct fuse_session *se, int clone_fd)
 {
 	struct fuse_loop_config config;