Only fix and show OUTPUT_PATH when it's defined

Author: lpenz

entrypoint

@@ -74,12 +74,12 @@ cargo llvm-cov --no-run --doctests "${OUTPUT_ARGS[@]}"
 # Print summary including doc tests:
 cargo llvm-cov --no-run --doctests
 
-sed -i "s@$GITHUB_WORKSPACE/@@" "$OUTPUT_PATH"
-
 if [ -n "$OUTPUT_PATH" ]; then
+    sed -i "s@$GITHUB_WORKSPACE/@@" "$OUTPUT_PATH"
+
     echo "::set-output name=report::$OUTPUT_PATH"
-fi
 
-if [ -n "$RUNNER_DEBUG" ]; then
-    cat "$OUTPUT_PATH"
+    if [ -n "$RUNNER_DEBUG" ]; then
+        cat "$OUTPUT_PATH"
+    fi
 fi