Fix to fix for schoolboy error in sockets examples. (#1040)

Commit 2c2670b "fixed" a schoolboy error in the example; however it didn't, it introduced an even more schoolboy error.  That boy needs to be punished.

Strange thing, of course, is that it passed testing because (a) the transmitted string is small enough that the while() loop doesn't have to loop and (b) the value of the first parameter happens to remain unchanged despite the error.

example/sockets/main.c

@@ -311,8 +311,7 @@ U_PORT_TEST_FUNCTION("[example]", "exampleSockets")
  // and print the echo that comes back
  uPortLog("Sending data...\n");
  while ((x >= 0) && (txSize > 0)) {
- x = uSockWrite(sock + (sizeof(message) - txSize),
- message, txSize);
+ x = uSockWrite(sock, message + (sizeof(message) - txSize), txSize);
  if (x > 0) {
  txSize -= x;
  }

example/sockets/main_dtls.c

@@ -352,8 +352,7 @@ U_PORT_TEST_FUNCTION("[example]", "exampleSocketsDtls")
  // and print the echo that comes back
  uPortLog("Sending data...\n");
  while ((x >= 0) && (txSize > 0)) {
- x = uSockWrite(sock + (sizeof(message) - txSize),
- message, txSize);
+ x = uSockWrite(sock, message + (sizeof(message) - txSize), txSize);
  if (x > 0) {
  txSize -= x;
  }

example/sockets/main_tls.c

@@ -352,8 +352,7 @@ U_PORT_TEST_FUNCTION("[example]", "exampleSocketsTls")
  // and print the echo that comes back
  uPortLog("Sending data...\n");
  while ((x >= 0) && (txSize > 0)) {
- x = uSockWrite(sock + (sizeof(message) - txSize),
- message, txSize);
+ x = uSockWrite(sock, message + (sizeof(message) - txSize), txSize);
  if (x > 0) {
  txSize -= x;
  }