Restore RawResponse speed
Restore RawResponse speed

RawResponse uses response.body from requests, which is pathologically
slow due to chardet (requests#2359). Since we're only interested in the
bytes, using response.content is faster. On a 3Mib file, this makes
a download_object() go from 40s to 4s.

Closes #1053

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