Revert "[master] Merge branch 'trac4106'"

This reverts commit 8f2a1f8a7a, reversing
changes made to ed7edadcbd.

This  merge introduced regressions in our build farm and revealed
issues in the DHCP4o6 IPC code. It also revealed some differences
in sockets handling under Linux and BSD. Rather than continue
patching this here, we should work on the branch to resolve all
issues and then merge 1.1.

src/bin/dhcp4/json_config_parser.cc

@@ -422,10 +422,9 @@ DhcpConfigParser* createGlobalDhcp4ConfigParser(const std::string& config_id,
     if ((config_id.compare("valid-lifetime") == 0)  ||
         (config_id.compare("renew-timer") == 0)  ||
         (config_id.compare("rebind-timer") == 0) ||
-        (config_id.compare("decline-probation-period") == 0) ||
-        (config_id.compare("dhcp4o6-port") == 0) )  {
+        (config_id.compare("decline-probation-period") == 0) )  {
         parser = new Uint32Parser(config_id,
-                                  globalContext()->uint32_values_);
+                                 globalContext()->uint32_values_);
     } else if (config_id.compare("interfaces-config") == 0) {
         parser = new IfacesConfigParser4();
     } else if (config_id.compare("subnet4") == 0) {
@@ -473,7 +472,6 @@ DhcpConfigParser* createGlobalDhcp4ConfigParser(const std::string& config_id,
 ///
 /// - echo-client-id
 /// - decline-probation-period
-/// - dhcp4o6-port
 void setGlobalParameters4() {
     // Although the function is modest for now, it is certain that the number
     // of global switches will increase over time, hence the name.
@@ -496,15 +494,6 @@ void setGlobalParameters4() {
     } catch (...) {
         // That's not really needed.
     }
-
-    // Set the DHCPv4-over-DHCPv6 interserver port.
-    try {
-        uint32_t dhcp4o6_port = globalContext()->uint32_values_
-            ->getOptionalParam("dhcp4o6-port", 0);
-        CfgMgr::instance().getStagingCfg()->setDhcp4o6Port(dhcp4o6_port);
-    } catch (...) {
-        // Ignore errors. This flag is optional
-    }
 }
 
 isc::data::ConstElementPtr