message: rhusb: Memory leak fix in sendCommand
  Fix for case where dataAvailable always returns true.  Previously, if
  this ever happened (eg mock platform), string resp is resized until the
  system is out of memory.
diff: @@ -127,18 +127,14 @@ string RHUSB::sendCommand(string cmd)
  {
  throw std::invalid_argument(std::string(__FUNCTION__) +
  ": cmd is empty!");
  - return "";
  }
  - // make sure string is CR terminated
  - if (cmd.at(cmd.size() - 1) != '\r')
  - cmd.append("\r");
  -
  - writeStr(cmd);
  + // Terminate the command with a carriage return
  + writeStr(cmd + "\r");
  string resp;
  // I see random timeouts with wait values below 250ms
  - while (dataAvailable(250))
  + while (dataAvailable(250) && (resp.size() < maxBuffer) )
  {
  resp += readStr(maxBuffer);
  }
  @@ -146,16 +142,14 @@ string RHUSB::sendCommand(string cmd)
  if (resp.empty())
  {
  throw std::runtime_error(std::string(__FUNCTION__) +
  - ": timed out waiting for response");
  - return "";
  + ": " + cmd + " response timed out");
  }
  // check that the last character is the prompt
  if (resp.at(resp.size() - 1) != '>')
  {
  throw std::runtime_error(std::string(__FUNCTION__) +
  - ": read from device corrupted");
  - return "";
  + ": " + cmd + " response corrupt");
  }
  // delete the last 3 characters, which should be '\r\n>'
  