BaseTools: Migrate to the new octal literal

Change the octal literals according to PEP3127
https://www.python.org/dev/peps/pep-3127/

Contributed-under: TianoCore Contribution Agreement 1.1
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>

BaseTools/Source/Python/Common/LongFilePathOs.py

@@ -41,7 +41,7 @@ def rmdir(path):
 def mkdir(path):
     return os.mkdir(LongFilePath(path))
 
-def makedirs(name, mode=0777):
+def makedirs(name, mode=0o777):
     return os.makedirs(LongFilePath(name), mode)
 
 def rename(old, new):