added ex_describe_volume_modifications() method
added ex_describe_volume_modifications() method

Kami/libcloud,andrewsomething/libcloud,ZuluPro/libcloud,pquentin/libcloud,andrewsomething/libcloud,andrewsomething/libcloud,t-tran/libcloud,pquentin/libcloud,StackPointCloud/libcloud,apache/libcloud,ZuluPro/libcloud,ByteInternet/libcloud,Kami/libcloud,apache/libcloud,mistio/libcloud,t-tran/libcloud,ZuluPro/libcloud,erjohnso/libcloud,illfelder/libcloud,illfelder/libcloud,StackPointCloud/libcloud,vongazman/libcloud,Kami/libcloud,pquentin/libcloud,vongazman/libcloud,Scalr/libcloud,mistio/libcloud,mistio/libcloud,ByteInternet/libcloud,erjohnso/libcloud,StackPointCloud/libcloud,Scalr/libcloud,vongazman/libcloud,illfelder/libcloud,erjohnso/libcloud,t-tran/libcloud,ByteInternet/libcloud,apache/libcloud,Scalr/libcloud