Switched from the old haskell HTTP library to http-conduit.

The hoary old HTTP library was only used when checking if an url exists,
when curl was not available. It had many problems, including not supporting
https at all.

Now, this is done using http-conduit for all urls that it supports. Falls
back to curl for any url that http-conduit doesn't like (probably ftp etc,
but could also be an url that its parser chokes on for whatever reason).

This adds a new dependency on http-conduit, but webdav support already
indirectly depended on that, and the s3-aws branch also uses it.

debian/changelog

@@ -39,6 +39,7 @@ git-annex (5.20140718) UNRELEASED; urgency=medium
   * git-annex-shell sendkey: Don't fail if a remote asks for a key to be sent
     that already has a transfer lock file indicating it's being sent to that
     remote. The remote may have moved between networks, or reconnected.
+  * Switched from the old haskell HTTP library to http-conduit.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 21 Jul 2014 14:41:26 -0400
 

debian/control

@@ -46,6 +46,7 @@ Build-Depends:
 	libghc-dns-dev,
 	libghc-case-insensitive-dev,
 	libghc-http-types-dev,
+	libghc-http-conduit-dev,
 	libghc-blaze-builder-dev,
 	libghc-crypto-api-dev,
 	libghc-network-multicast-dev,
@@ -55,7 +56,6 @@ Build-Depends:
 	libghc-gnutls-dev (>= 0.1.4),
 	libghc-xml-types-dev,
 	libghc-async-dev,
-	libghc-http-dev,
 	libghc-feed-dev (>= 0.3.9.2),
 	libghc-regex-tdfa-dev [!mipsel !s390],
 	libghc-regex-compat-dev [mipsel s390],