See also bug 1361495 - PR_SI_HOSTNAME is implemented in NSPR on
Windows as initializing winsock which can be janky. There don't seem
to be any users of this property, and it has tracker concerns anyhow -
so remove it.
MozReview-Commit-ID: S2AwzMUgYk
--HG--
extra : rebase_source : 552bed219913f40c002b807be3239d4666a5284b