[FIX] server: prevent inotify watches leak

Before this commit the PyInotify filesystem watcher used by the code
autoreload feature (`--dev=reload`) would not get a chance to free
it's inotify watches before the reexec, hence at each reexec triggered
by a code reload the inotify watches where accumulated until potentially
reaching the kernel limit `fs.inotify.max_user_watches`.

This patch ensures that inotify properly closes it's file descriptor
before we reexec:
https://github.com/dsoprea/PyInotify/blob/f77596a/inotify/adapters.py#L79

closes odoo/odoo#71302

X-original-commit: 8703ff1e3d9be6f2f5fce2e8c4e62589b05133fb
Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

odoo/service/server.py

@@ -296,6 +296,7 @@ class FSWatcherInotify(FSWatcherBase):
     def stop(self):
         self.started = False
         self.thread.join()
+        del self.watcher  # ensures inotify watches are freed up before reexec
 
 
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