Fix compatibility with Ethernet.begin(nullptr) by removing begin(const char* hostname) method.

Author: Channel59

libraries/Ethernet/src/Ethernet.cpp

@@ -29,12 +29,6 @@ int arduino::EthernetClass::setHostname(const char* hostname) {
   return 1;
 }
 
-int arduino::EthernetClass::begin(const char* hostname) {
-  eth_if->set_hostname(hostname);
-  auto ret = begin();
-  return ret;
-}
-
 int arduino::EthernetClass::begin(uint8_t *mac, IPAddress ip) {
   IPAddress dns = ip;
   dns[3] = 1;

libraries/Ethernet/src/Ethernet.h

@@ -63,7 +63,6 @@ class EthernetClass : public MbedSocketClass {
   // gain the rest of the configuration through DHCP.
   // Returns 0 if the DHCP configuration failed, and 1 if it succeeded
   int begin(uint8_t *mac = nullptr, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
-  int begin(const char* hostname);
   EthernetLinkStatus linkStatus();
   EthernetHardwareStatus hardwareStatus();