Replace file.flush() calls with flush_sync() helper

Calls to `os.fsync(f.fileno())` need to be accompained by `f.flush()`.

Commit 8bbeedc93f introduces the helper
`ipapython.ipautil.flush_sync()`, which handles all calls in the right
order.

However, `flush_sync()` takes as parameter a file object with fileno
and name, where name must be a path to the file, this isn't possible
in some cases where file descriptors are used.

Issue: https://pagure.io/freeipa/issue/7251

Signed-off-by: Armando Neto <abiagion@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>

ipaclient/remote_plugins/schema.py

@@ -22,6 +22,7 @@ from ipalib.errors import SchemaUpToDate
 from ipalib.frontend import Object
 from ipalib.output import Output
 from ipalib.parameters import DefaultFrom, Flag, Password, Str
+from ipapython import ipautil
 from ipapython.ipautil import fsdecode
 from ipapython.dn import DN
 from ipapython.dnsutil import DNSName
@@ -492,8 +493,7 @@ class Schema(object):
                                          dir=self._DIR, delete=False) as f:
             try:
                 self._write_schema_data(f)
-                f.flush()
-                os.fsync(f.fileno())
+                ipautil.flush_sync(f)
                 f.close()
             except Exception:
                 os.unlink(f.name)