curl multi_select bug in php 5.3.18+

curl_multi_select() may return -1 forever until you call curl_multi_exec()
See https://bugs.php.net/bug.php?id=63411
https://bugs.php.net/bug.php?id=61141
Merge pull request #10 from aslamsayyed/patch-1

curl multi_select bug in php 5.3.18+