fix output unbound local error

Author: shenxianpeng

cpp_linter_hooks/clang_format.py

@@ -14,6 +14,8 @@ def run_clang_format(args) -> int:
             continue
         command.append(arg)
 
+    retval = 0
+    output = ""
     try:
         if "--dry-run" in command:
             sp = subprocess.run(command, stdout=subprocess.PIPE)

cpp_linter_hooks/clang_tidy.py

@@ -13,6 +13,9 @@ def run_clang_tidy(args) -> int:
         if arg == expect_version or arg.startswith("--version"):
             continue
         command.append(arg)
+
+    retval = 0
+    output = ""
     try:
         sp = subprocess.run(command, stdout=subprocess.PIPE)
         retval = sp.returncode