GSMClient GSMSSLClient: align constructor to other Client classes

  Remove the possibility to set socket timeout from constructor.
  The preferred way should be using setSocketTimeout() method.

Author: pennam

libraries/GSM/src/GSMClient.cpp

@@ -26,10 +26,6 @@
 namespace arduino {
 
 class GSMClient : public AClient {
-public:
-  GSMClient();
-
-private:
   NetworkInterface *getNetwork() {
     return GSM.getNetwork();
   }

libraries/GSM/src/GSMClient.h

@@ -28,9 +28,6 @@ extern const char CA_CERTIFICATES[];
 namespace arduino {
 
 class GSMSSLClient : public arduino::ASslClient {
-public:
-  GSMSSLClient();
-
 private:
   NetworkInterface *getNetwork() {
     return GSM.getNetwork();