feat(openid): swicth to libcurl for http request

It was using an internal library before and there were too much errors due to incomplete http's protocol implementation

SoObjects/SOGo/SOGoSystemDefaults.m

@@ -779,6 +779,15 @@ NSComparisonResult languageSort(id el1, id el2, void *context)
   return emailParam;
 }
 
+- (NSString *) openIdHttpVersion
+{
+  NSString *httpVersion;
+  httpVersion = [self stringForKey: @"SOGoOpenIdHttpVersion"];
+  if(!httpVersion)
+    httpVersion = @"HTTP/1.1";
+  return httpVersion;
+}
+
 - (BOOL) openIdLogoutEnabled: (NSString *) _domain
 {
   if(_domain && [self doesLoginTypeByDomain])