RHEL 7: Remove User-Mode Linux (RHBZ#1144197).

This isn't supported in RHEL 7.

src/launch-uml.c

@@ -136,6 +136,12 @@ uml_supported (guestfs_h *g)
 static int
 launch_uml (guestfs_h *g, void *datav, const char *arg)
 {
+  error (g,
+	 "launch: In RHEL, only the 'libvirt' or 'direct' method is supported.\n"
+	 "In particular, User-Mode Linux (UML) is not supported.");
+  return -1;
+
+#if 0
   struct backend_uml_data *data = datav;
   CLEANUP_FREE_STRINGSBUF DECLARE_STRINGSBUF (cmdline);
   int console_sock = -1, daemon_sock = -1;
@@ -503,6 +509,7 @@ launch_uml (guestfs_h *g, void *datav, const char *arg)
   }
   g->state = CONFIG;
   return -1;
+#endif
 }
 
 /* This is called from the forked subprocess just before vmlinux runs,