scripts/qmp/qom-fuse: Unbreak import of QEMUMonitorProtocol

Commit c7b942d7 "scripts/qmp: Fix shebang and imports" messed with
it for reasons I don't quite understand.  I do understand how it fails
now: it neglects to import sys.  Fix that.

It now fails because it expects an old version of module fuse.  That's
next.

Fixes: c7b942d7
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200723142738.1868568-2-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

scripts/qmp/qom-fuse

@@ -13,7 +13,7 @@
 
 import fuse, stat
 from fuse import Fuse
-import os, posix
+import os, posix, sys
 from errno import *
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
@@ -134,7 +134,7 @@ class QOMFS(Fuse):
             yield fuse.Direntry(str(item['name']))
 
 if __name__ == '__main__':
-    import sys, os
+    import os
 
     fs = QOMFS(QEMUMonitorProtocol(os.environ['QMP_SOCKET']))
     fs.main(sys.argv)