charmloader: log fails to file

Log all charms and bundles that failed the ingestion process. With err descriptions if possible.
lppublish: fix publishing of promulgated charms
Merge pull request #108 from rogpeppe/049-fix-closed-body

lppublish: fix publishing of promulgated charms

The same body can be posted several times, but it was closed after
the first request. This stops that happening.
internal/v4: implement debug/status endpoint
Merge branch 'v4' into log-all-loader-fails-to-file
name log file .err not -err
minor fixes for review
actually log
Merge pull request #109 from rogpeppe/050-debug-status

internal/v4: implement debug/status endpoint

As newly documented in the charm store.
Not all entries are implemented yet.
Merge pull request #103 from jrwren/log-all-loader-fails-to-file

charmloader: log fails to file

Log all charms and bundles that failed the ingestion process. With err descriptions if possible.