remove ulimit command that breaks git on cedar somehow

Hi @cburgard, there's an issue @mbasso and I see on our cluster, which has been there for years (before the R25 upgrade stuff), and today we finally got around to tracking it down.

The issue, which appears when using HWWAnalysisCode:

• login: git works fine
• login + setupATLAS: git works fine
• login + setupATLAS + asetup: git works fine
• login + setupATLAS + asetup + source setupAnalysis.sh: git breaks (no git commands run properly, for example git status gives fatal: unable to create threaded lstat: Resource temporarily unavailable)

So far we've just been using a second terminal where we don't run setupAnalysis.sh, which works ok but is kind of annoying.

Thoughts about a solution:

• setupAnalysis.sh sources all the setup.sh scripts of submodules. We tried commenting them out one by one, and it seems the problem is in RooFitUtils
• Within the RooFitUtils setup.sh we did the same process of commenting lines to isolate the problem, and found it was the ulimit line you'll see removed in the changes here

This line must have been added for some reason in the past, do you know why exactly? There's a comment which mentions "memory allocation issues with RooWorkspaces", but also that it's "not really related to the package" so maybe shouldn't be in the setup script to set up the package... I'm not sure.

If we remove it (as in the current version of this MR), do you figure we'll run into the error with RooWorkspaces? We could potentially add an if hostname == Cedar type block, but ideally (imo) we'd try to keep this package non-machine-specific.

Let us know what you think & if there's a better solution than just removing this line 😄