Added comment to _utc_timestamp method. Closes #879
Added comment to _utc_timestamp method.
Closes #879

apache/libcloud,vongazman/libcloud,samuelchong/libcloud,samuelchong/libcloud,illfelder/libcloud,ByteInternet/libcloud,mgogoulos/libcloud,t-tran/libcloud,SecurityCompass/libcloud,watermelo/libcloud,apache/libcloud,t-tran/libcloud,Kami/libcloud,ByteInternet/libcloud,StackPointCloud/libcloud,SecurityCompass/libcloud,mistio/libcloud,erjohnso/libcloud,watermelo/libcloud,ZuluPro/libcloud,Kami/libcloud,ByteInternet/libcloud,ZuluPro/libcloud,andrewsomething/libcloud,techhat/libcloud,samuelchong/libcloud,techhat/libcloud,t-tran/libcloud,mgogoulos/libcloud,SecurityCompass/libcloud,watermelo/libcloud,ZuluPro/libcloud,andrewsomething/libcloud,mgogoulos/libcloud,pquentin/libcloud,Scalr/libcloud,mistio/libcloud,mistio/libcloud,Kami/libcloud,illfelder/libcloud,erjohnso/libcloud,vongazman/libcloud,andrewsomething/libcloud,StackPointCloud/libcloud,illfelder/libcloud,StackPointCloud/libcloud,pquentin/libcloud,vongazman/libcloud,pquentin/libcloud,techhat/libcloud,erjohnso/libcloud,Scalr/libcloud,apache/libcloud,Scalr/libcloud