Refactor get_instance_vhd from a closure method to instance method so it can be tested more easily.
Refactor get_instance_vhd from a closure method to instance method so it
can be tested more easily.

Kami/libcloud,ByteInternet/libcloud,ByteInternet/libcloud,pquentin/libcloud,vongazman/libcloud,apache/libcloud,mistio/libcloud,Kami/libcloud,apache/libcloud,andrewsomething/libcloud,Kami/libcloud,ByteInternet/libcloud,erjohnso/libcloud,ZuluPro/libcloud,vongazman/libcloud,apache/libcloud,pquentin/libcloud,Scalr/libcloud,vongazman/libcloud,StackPointCloud/libcloud,mistio/libcloud,ZuluPro/libcloud,StackPointCloud/libcloud,StackPointCloud/libcloud,erjohnso/libcloud,Scalr/libcloud,andrewsomething/libcloud,erjohnso/libcloud,mistio/libcloud,ZuluPro/libcloud,andrewsomething/libcloud,Scalr/libcloud,pquentin/libcloud