DEV: revert bundler to 1.7.3

DEV: revert bundler to 1.7.3

At the moment bundler 2.0 is not compatible with:

We plan to get this fixed but in the mean time do not upgrade.

followup to 2a7065c5

diff --git a/Gemfile.lock b/Gemfile.lock
index fbc5593..b625d8d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -533,4 +533,4 @@ DEPENDENCIES
-   2.0.1
+   1.17.3

GitHub sha: a4627c3d


is 2.0 fine if one doesnt use the backup plugin? or would it be safer to downgrade the rpm also to 1.17?

I am unsure how to answer this cause we simply did not test this, very hard to tell what other side effects will pop up.