[bugfix] Make attrs() utility function pass when an AttributeError is raised

[jjotero]

When the LoggerAdapter class calls the attrs method from reframe/utility/__init__.py it retrieves the values of the data descriptors from an object.

With the recent addition of the variable built-in, variables can be set as required (undefined), which means that a call to getattr on these variables will raise an AttributeError. When any of these required variables is not set when LoggerAdapter class attempts to fetch all the descriptors from a test, this raises a very ugly AttributeError.

For this reason, this attrs function from utility must pass if its call to getattr raises an AttributeError.

The unit test has also been changed accordingly.

[vkarak]

lgtm

[codecov-io]

Codecov Report

Merging #1802 (70a5edd) into master (c5817eb) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1802   +/-   ##
=======================================
  Coverage   87.57%   87.57%           
=======================================
  Files          49       49           
  Lines        7919     7922    +3     
=======================================
+ Hits         6935     6938    +3     
  Misses        984      984           

Impacted Files	Coverage Δ
reframe/utility/__init__.py	91.95% <100.00%> (+0.04%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c5817eb...70a5edd. Read the comment docs.

[vkarak]

@jenkins-cscs retry none