Config string parsing fails if value contains an '='

[Jean-Baptiste Lallement]

Config string parsing fails if the value of a parameter contains an '='.

For example with ubuntu-sanity-tests if the WiFi passphrase contains an '=' it fails with:
=====
Traceback (most recent call last):
  File "/tmp/adt-run.YAwQfE/build.3M3/real-tree/ubuntu_sanity_tests/tests/test_settings_wizard.py", line 46, in setUp
    self._apply_default_config()
  File "/tmp/adt-run.YAwQfE/build.3M3/real-tree/ubuntu_sanity_tests/tests/test_settings_wizard.py", line 55, in _apply_default_config
    config = get_test_configuration()
  File "/tmp/adt-run.YAwQfE/deps/usr/lib/python3/dist-packages/autopilot/_config.py", line 67, in get_test_configuration
    return ConfigDict(_test_config_string)
  File "/tmp/adt-run.YAwQfE/deps/usr/lib/python3/dist-packages/autopilot/_config.py", line 84, in __init__
    "Invalid configuration string '{}'".format(config_string)
ValueError: Invalid configuration string 'device_password=0000,output_dir=./results,sim_0_pin=0000,wifi_password=password_with_an_=_sign,wifi_ssid=MyAccessPoint'
=====

This is because the string key=value is split on '=' without limit. A possible patch is:
====
=== modified file 'autopilot/_config.py'
--- autopilot/_config.py 2014-05-21 07:42:24 +0000
+++ autopilot/_config.py 2015-01-07 14:05:34 +0000
@@ -74,7 +74,7 @@
         for item in config_string.split(','):
             if not item:
                 continue
- parts = item.split('=')
+ parts = item.split('=', 1)
             if len(parts) == 1:
                 self._data[parts[0].lstrip()] = '1'
             elif len(parts) == 2:
====

[PS Jenkins bot (ps-jenkins)]

Fix committed into lp:autopilot at revision None, scheduled for release in autopilot, milestone 1.4