agent: Ensure MS_REMOUNT is respected

When updating ephemeral storages, MS_REMOUNT is explicitly passed as,
for instance, `/dev/shm` should be remounted after memory is hotplugged.

Till now Kata Containers has been explicitly ignoring such updates,
leading to the containers' `/dev/shm` having the size of "half of the
memory allocated, during the startup time", which goes against the
expected behaviour.

Signed-off-by: Fabiano Fidêncio <fidencio@northflank.com>

src/agent/src/mount.rs

@@ -88,7 +88,7 @@ pub fn baremount(
 
     let destination_str = destination.to_string_lossy();
     if let Ok(m) = get_linux_mount_info(destination_str.deref()) {
-        if m.fs_type == fs_type {
+        if m.fs_type == fs_type && !flags.contains(MsFlags::MS_REMOUNT) {
             slog_info!(logger, "{source:?} is already mounted at {destination:?}");
             return Ok(());
         }