Improve cvmfs_info function

[vitodb]

This PR is to address #600.

1. it reorganizes the way osgstorage (OSFD/StashCache) CVMFS repos are handled to make sure we only check them if the group used by jobs has such repo;
2. it makes sure the CVMFS info are printed only for failed jobs;
3. it adds a preamble to tell users the CVMFS info log are not logs generated by their batch script
4. it checks RCDS repos

[vitodb]

Test jobs for this update are available here

[shreyb]

This looks good. Have you checked to see what this looks like if we submit a gm2 job, for example, and there is no StashCache repo for the VO?

[vitodb]

Log example of job logs for gm2 that doesn't have StashCache repo are here