Merge branch 'fc/remote-helper-refmap' into next
Allow remote-helper/fast-import based transport to rename the refs
while transferring the history.
* fc/remote-helper-refmap:
transport-helper: remove unnecessary strbuf resets
transport-helper: add support to delete branches
fast-export: add support to delete refs
fast-import: add support to delete refs
transport-helper: add support to push symbolic refs
transport-helper: add support for old:new refspec
fast-export: add new --refspec option
fast-export: improve argument parsing