revert to atom filepath because atom-linter bug

Author: mschuchard

lib/main.js

@@ -94,7 +94,8 @@ export default {
                   severity: issue.kind,
                   excerpt: issue.message,
                   location: {
-                    file: issue.fullpath,
+                    // bug in atom-linter cannot use issue.path
+                    file: filePath,
                     position: helpers.generateRange(activeEditor, line, col),
                   },
                 });