bundlespec: fix the "streamv2" and "streamv3-exp" variant
In c4aab3661f25, we broken this feature by adding unicode instead of bytes to
the dictionary.
On the other hand, this feature was never tested, so augment the tests to tests
this.
#!/usr/bin/env python3
import errno
import os
import sys
for f in sys.argv[1:]:
try:
print(f, '->', os.readlink(f))
except OSError as err:
if err.errno != errno.EINVAL:
raise
print(f, '->', f, 'not a symlink')
sys.exit(0)