Fix regression introduced in 2641bf825908cf4d53e10453c9355c81235c948b

(thx @AltGr for noticing)
Merge branch 'master' of github.com:OCamlPro/opam
Merge pull request #739 from AltGr/mk-repo-check

opam-admin make: first check that there is a repo
Fix installation of packages without archive files, upstream archive but with overlay files.

Typical example: base-* packages when installing using a git repository.

Fix #735
Merge branch 'master' of github.com:OCamlPro/opam
Merge pull request #738 from AltGr/opam-admin-fix-man

Fixed man-pages for opam-admin
Don't fail is a broken lock suddendly disapear
Merge branch 'master' of github.com:OCamlPro/opam
Updated CHANGES