Remove unnecessary exception for test function names

As we are no longer running linters over test modules, this exception
(to allow long method/function names as long as they start with "test_")
is no longer needed.

.prospector.yaml

@@ -27,14 +27,6 @@ pylint:
     # - parser: common in modules that use argparse
     #
     good-names: _,i,j,k,v,e,db,fn,fp,log,parser
-
-    # Allow longer function and method names.
-    #
-    # By default PyLint doesn't allow function or method names longer than 30
-    # chars, but lots of test methods do (and should) have longer names. It'd
-    # be better to restrict this setting to tests only.
-    method-rgx: '((test_[a-z0-9_]{2,59})|([a-z_][a-z0-9_]{2,30}))$'
-    function-rgx: '((test_[a-z0-9_]{2,59})|([a-z_][a-z0-9_]{2,30}))$'
 pep257:
   disable:
     - D100  # Missing docstring in public module