Set error when invalid timeout value is given to redisConnectWithTimeout

Closes #154

This commit properly sets the error value inside of
redisContextWaitReady when an invalid sec or usec value is provided.
Tests for each case are provided to demonstrate that the issue is
properly fixed and to avoid regression.

Signed-off-by: Aaron Bedra <aaron@aaronbedra.com>
Merge pull request #156 from abedra/master

Set error on invalid timval values for redisConnectWithTimeout (Fixes #154)