C version of xenstored had this ability since 61aaed0d5 ("Allow
XS_INTRODUCE to be used for rebinding the xenstore evtchn.") from 2007.
Copy it as is to Ocaml version.
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>