[Endless] gpt-auto-generator: Make /boot a persistent mount

When using staged deployments, ostree updates the boot loader entries during
shutdown from a systemd unit. That's proven to be very fragile when /boot is an
automount:

* Once automount units are scheduled to be stopped, systemd ignores
  notifications from autofs that the mount is needed. That means that if the
  mount isn't active when the shutdown phase begins, finalizing the deployment
  will fail.

* When a separate mount namespace is in use, autofs does not see the mount as
  active and notifies systemd that the mount is expired so it will be
  unmounted. Since systemd often starts units in separate mount namespaces,
  this can either cause the finalizing unit to be triggered early and hang or
  fail if it hasn't completed by the time the mount expires.

Although the goal of keeping the ESP unmounted is worthy since it's on a VFAT
filesystem, having systemd not mount /boot when needed or unmounted while it's
still needed is worse. This changes the /boot mount (either the ESP or XBOOTLDR
partition) to be persistent.

https://phabricator.endlessm.com/T33136

src/gpt-auto-generator/gpt-auto-generator.c

@@ -473,14 +473,14 @@ static int add_xbootldr(DissectedPartition *p) {
         if (r > 0)
                 return 0;
 
-        return add_automount("boot",
-                             p->node,
-                             "/boot",
-                             p->fstype,
-                             true,
-                             esp_or_xbootldr_options(p),
-                             "Boot Loader Partition",
-                             120 * USEC_PER_SEC);
+        return add_mount("boot",
+                         p->node,
+                         "/boot",
+                         p->fstype,
+                         true,
+                         esp_or_xbootldr_options(p),
+                         "Boot Loader Partition",
+                         SPECIAL_LOCAL_FS_TARGET);
 }
 
 #if ENABLE_EFI
@@ -547,14 +547,24 @@ static int add_esp(DissectedPartition *p, bool has_xbootldr) {
         } else
                 log_debug("Not an EFI boot, skipping ESP check.");
 
-        return add_automount(id,
-                             p->node,
-                             esp_path,
-                             p->fstype,
-                             true,
-                             esp_or_xbootldr_options(p),
-                             "EFI System Partition Automount",
-                             120 * USEC_PER_SEC);
+        if (streq(esp_path, "/boot"))
+                return add_mount(id,
+                                 p->node,
+                                 esp_path,
+                                 p->fstype,
+                                 true,
+                                 esp_or_xbootldr_options(p),
+                                 "EFI System Partition",
+                                 SPECIAL_LOCAL_FS_TARGET);
+        else
+                return add_automount(id,
+                                     p->node,
+                                     esp_path,
+                                     p->fstype,
+                                     true,
+                                     esp_or_xbootldr_options(p),
+                                     "EFI System Partition Automount",
+                                     120 * USEC_PER_SEC);
 }
 #else
 static int add_esp(DissectedPartition *p, bool has_xbootldr) {