Fixes stream load memory leak in WifiSecureClient for SSL CACert, Certificate, and

Private Key. Issue presented during any subsequent invocation of loadCACert, loadCertificate, and
loadPrivateKey, respectively, after the first invocation.

Author: beeboopx

Diff for: libraries/WiFiClientSecure/src/WiFiClientSecure.cpp

@@ -315,6 +315,7 @@ char *WiFiClientSecure::_streamLoad(Stream& stream, size_t size) {
 }
 
 bool WiFiClientSecure::loadCACert(Stream& stream, size_t size) {
+  if (_CA_cert != NULL) free(const_cast<char*>(_CA_cert));
   char *dest = _streamLoad(stream, size);
   bool ret = false;
   if (dest) {
@@ -325,6 +326,7 @@ bool WiFiClientSecure::loadCACert(Stream& stream, size_t size) {
 }
 
 bool WiFiClientSecure::loadCertificate(Stream& stream, size_t size) {
+  if (_cert != NULL) free(const_cast<char*>(_cert));
   char *dest = _streamLoad(stream, size);
   bool ret = false;
   if (dest) {
@@ -335,6 +337,7 @@ bool WiFiClientSecure::loadCertificate(Stream& stream, size_t size) {
 }
 
 bool WiFiClientSecure::loadPrivateKey(Stream& stream, size_t size) {
+  if (_private_key != NULL) free(const_cast<char*>(_private_key));
   char *dest = _streamLoad(stream, size);
   bool ret = false;
   if (dest) {