Fix building instance when hive is a submodule

gitdir related fixes (seems it changed location of underlying .git repo being specific to submodules and now they are held in root .git subdirectory). This opened an issue when docker image (specific only to some submodule) was built, since it didn't have an access to the .git location what was needed to properly compile in git revisions.

Requires common-ci-configuration!33 (merged)