add-apt-repository backtraces on PPA with utf8 characters

On a brand new trusty container:

root@apatest3:~# add-apt-repository ppa:ondrej/apache2
 This branch follows latest PHP packages as maintained by the Debian Apache2 team.

It also includes some widely used Apache 2 modules (if you need some other feel free to send me a request).

If you need to stay with PHP 5 you can use the PHP repository:
https://launchpad.net/~ondrej/+archive/php5

BUGS&FEATURES: This PPA now has a issue tracker: https://deb.sury.org/pages/bugreporting.html

PLEASE READ: If you like my work and want to give me a little motivation, please consider donating: https://deb.sury.org/pages/donate.html
 More info: https://launchpad.net/~ondrej/+archive/ubuntu/apache2
Press [ENTER] to continue or ctrl-c to cancel adding it

gpg: keyring `/tmp/tmprl8b6i1r/secring.gpg' created
gpg: keyring `/tmp/tmprl8b6i1r/pubring.gpg' created
gpg: requesting key E5267A6C from hkp server keyserver.ubuntu.com
gpg: /tmp/tmprl8b6i1r/trustdb.gpg: trustdb created
gpg: key E5267A6C: public key "Launchpad PPA for Ond\xc5\x99ej Sur▒" imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python3.4/threading.py", line 920, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.4/threading.py", line 868, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 687, in addkey_func
    func(**kwargs)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 370, in add_key
    return apsk.add_ppa_signing_key()
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 261, in add_ppa_signing_key
    tmp_export_keyring, signing_key_fingerprint, tmp_keyring_dir):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 210, in _verify_fingerprint
    got_fingerprints = self._get_fingerprints(keyring, keyring_dir)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 202, in _get_fingerprints
    output = subprocess.check_output(cmd, universal_newlines=True)
  File "/usr/lib/python3.4/subprocess.py", line 605, in check_output
    output, unused_err = process.communicate(inputdata, timeout=timeout)
  File "/usr/lib/python3.4/subprocess.py", line 936, in communicate
    stdout = _eintr_retry_call(self.stdout.read)
  File "/usr/lib/python3.4/subprocess.py", line 487, in _eintr_retry_call
    return func(*args)
  File "/usr/lib/python3.4/encodings/ascii.py", line 26, in decode
    return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc5 in position 92: ordinal not in range(128)

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: software-properties-common 0.92.37.5
ProcVersionSignature: Ubuntu 3.19.0-23.24-generic 3.19.8-ckt2
Uname: Linux 3.19.0-23-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.15
Architecture: amd64
Date: Mon Oct 26 18:22:33 2015
PackageArchitecture: all
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
SourcePackage: software-properties
UpgradeStatus: No upgrade log present (probably fresh install)