Don't use strerror on IOError object

Author: mwaskom

nipype/interfaces/io.py

@@ -86,7 +86,7 @@ def copytree(src, dst, use_hardlink=False):
  copyfile(srcname, dstname, True, hashmethod='content',
  use_hardlink=use_hardlink)
  except (IOError, os.error) as why:
- errors.append((srcname, dstname, why.strerror))
+ errors.append((srcname, dstname, str(why)))
  # catch the Error from the recursive copytree so that we can
  # continue with other files
  except Exception as err: