add FIXME to RecipeCorrectButBuildScriptBroken

should we inherit from BrokenLinkage or ExternalLinkage?
BUGFIX: fix NameError due to typo

s/link_error_handler/link_errors_handler/
BUGFIX: invert logic for ignoring link errors
add FIXME re observed LinkErrors repr
WORKAROUND: ensure python exists before proceeding

to better pinpoint why the test is failing