Handle bytes from socket.gethostname() in GUIDerator.reseed

[uttam12331]

Summary

Closes #295.

On some platforms/configurations socket.gethostname() returns bytes rather than str. GUIDerator.reseed() joins it into the salt with str.join():

self.salt = '-'.join([str(self.pid),
                      socket.gethostname() or '<nohostname>',
                      ...])

which raises TypeError: sequence item 1: expected str instance, bytes found. Because a module-level GUIDerator() is created at import time, this can break importing boltons.iterutils entirely on affected systems.

Fix

Decode the hostname to str when it comes back as bytes:

hostname = socket.gethostname()
if isinstance(hostname, bytes):
    hostname = hostname.decode('utf8', 'replace')

Tests

Added test_guiderator_bytes_hostname (monkeypatches socket.gethostname to return b'myhost') asserting a valid hex GUID is produced without raising.

Verified locally: pytest tests/test_iterutils.py → 45 passed.