lfs: use the localstore download method to transfer from remote stores Both gitlfsremote and file based remotes benefit from not requiring the whole file in memory (though the whole file is still loaded when passing through the revlog interface). With a method specific to downloading from a remote store, the misleading 'use hg verify' hint is removed. The behavior is otherwise unchanged, in that a download from both remote store types will yield a copy of the blob via util.atomictempfile. There's no response payload defined for the non 'download' actions, but the previous code attempted to read the payload in this case anyway. This refactored code made that more obvious, so any payload is printed as a debug message, just in case.