lib/deploy: Don't include version twice in bootmenu title

In Silverblue right now, the boot menu title looks like this:

    Fedora 29.20190301.0 (Workstation Edition) 29.20190301.0 (ostree)

This is because RPM-OSTree's `mutate-os-release` feature is enabled,
which injects the OSTree version string directly into `VERSION` and
`PRETTY_NAME`. So appending the version string again is a bit redundant.
Let's just do a simple substring check here before adding the version to
the title.

Closes: #1829
Approved by: cgwalters

src/libostree/ostree-sysroot-deploy.c

@@ -1739,7 +1739,7 @@ install_deployment_kernel (OstreeSysroot   *sysroot,
    *     (specifically, it looks for the substring "(ostree"), so further
    *     changes to the title format may require updating that backend. */
   g_autoptr(GString) title_key = g_string_new (val);
-  if (deployment_version && *deployment_version)
+  if (deployment_version && *deployment_version && !strstr (val, deployment_version))
     {
       g_string_append_c (title_key, ' ');
       g_string_append (title_key, deployment_version);