cactch ConfigReader exception in sr71
Merge pull request #14 from makocchi-git/catch_config_ioerror

catch ConfigReader exception in sr71
Add our yum repository URL
Get rid of "ipaddr" module from requires

Because of

* ipaddr is used to validate whether given value is IP Address
* `hostname` parameter in config may be hostanme or IP Address
* "python-ipaddr" RPM doesn't exist in AWS RPM repository
Merge pull request #16 from JumpeiArashi/get-rid-of-ipaddr

Get rid of "ipaddr" module from requires