mirrors: patches are now properly added to mirrors (#8993)

* This fixes a number of bugs:

  * Patches were not properly downloaded and added to mirrors.

  * Mirror create didn't respect `list_url` in packages

  * Update the `spack mirror` command to add all packages in the
    concretized DAG (where originally it only added the package specified
    by the user). This is required in order to collect patches that are specified
    by dependents. Example:
      * if X->Y and X requires a patch on Y called Pxy, then Pxy will only
        be discovered if you create a mirror with X.

  * replace confusing --one-version-per-spec option for `spack mirror create`
    with --versions-per-spec; support retrieving multiple versions for 
    concrete specs

* Implementation details:

  * `spack mirror create` now uses regular staging logic to download files 
    into a mirror, instead of reimplementing it in `add_single_spec`.

  * use a separate resource caching object to keep track of new
    resources and already-existing resources; also accepts storing
    resources retrieved from a cache (unlike the local cache)

  * mirror cache object now stores resources that are considered
    non-cachable, like (e.g. the tip of a branch);

  * the 'create' function of the mirror module no longer traverses
    dependencies since this was already handled by the 'mirror' command; 

  * Change handling of `--no-checksum`:

    * now that 'mirror create' uses stages, the mirror tests disable
      checksums when creating the mirror

    * remove `no_checksum` argument from library functions - this is now
      handled at the Spack-command-level (like for 'spack install')

0 files changed, 0 insertions, 0 deletions