Avoid an infinite redirect in $wgSecureLogin handling

If, for some reason, (e.g. https://gerrit.wikimedia.org/r/#/c/133205/ )
HTTPS requests are not recognised as such and WebRequest::getProtocol()
unconditionally returns "http", use the fromhttp parameter to avoid an
infinite redirect loop.

Change-Id: Iefbf679ef995f5e347e2b9c3f1f5a5b22055e107
Merge "Avoid an infinite redirect in $wgSecureLogin handling"