Bug 948912 - Owerwrite the socket method 'sendall' to retray if we hit the EAGAIN exception while sending report. r=hskupin

Due to an issue in urllib2 on mac we get EAGAIN (Errno 35) exception when
sending bigger reports https://github.com/shazow/urllib3/issues/63
Fix from https://github.com/shazow/urllib3/issues/63#issuecomment-15447770