Improve error reporting of azure auth errors.
Improve error reporting of azure auth errors.

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