Merge branch 'jc/fetch-ignore-symref' into maint

Merge branch 'jc/fetch-ignore-symref' into maint

"git fetch --mirror" and fetch that uses other forms of refspec with
wildcard used to attempt to update a symbolic ref that match the
wildcard on the receiving end, which made little sense (the real ref
that is pointed at by the symbolic ref would be updated anyway).

Symbolic refs no longer are affected by such a fetch.

* jc/fetch-ignore-symref:
  fetch: ignore wildcarded refspecs that update local symbolic refs