Fix Western Australia parser

[con-cat]

Fixes AU-WA in #2134

I've made a correction to an api call in lib/AU_solar.py to get the previous day's solar data - the AUS-WA parser now works for me when I test locally.

[jarek]

From a brief look this looks good to me :)

(SOLAR_URL is 'http://pv-map.apvi.org.au/data' so that format() call that has been removed would always have been a no-op - might have been copied from AEMO parser)

Tail of output:

 {'capacity': {'coal': 1561.2,
               'gas': 2954.4,
               'oil': 122.90000000000002,
               'solar': 5.744,
               'unknown': 15.52,
               'wind': 132.889},
  'datetime': datetime.datetime(2020, 1, 7, 8, 0, tzinfo=tzfile('/usr/share/zoneinfo/Australia/Perth')),
  'production': {'coal': 947.484,
                 'gas': 796.7409999999999,
                 'oil': 0.0,
                 'solar': 187.831,
                 'unknown': 10.045,
                 'wind': 108.16},
  'source': 'wa.aemo.com.au, pv-map.apvi.org.au',
  'storage': {},
  'zoneKey': 'AUS-WA'},
 {'capacity': {'coal': 1561.2,
               'gas': 2954.4,
               'oil': 122.90000000000002,
               'solar': 5.744,
               'unknown': 15.52,
               'wind': 132.889},
  'datetime': datetime.datetime(2020, 1, 7, 8, 30, tzinfo=tzfile('/usr/share/zoneinfo/Australia/Perth')),
  'production': {'coal': 928.6159999999999,
                 'gas': 783.6590000000001,
                 'oil': 0.0,
                 'solar': 244.194,
                 'unknown': 10.053,
                 'wind': 131.36100000000002},
  'source': 'wa.aemo.com.au, pv-map.apvi.org.au',
  'storage': {},
  'zoneKey': 'AUS-WA'},
 {'capacity': {'coal': 1561.2,
               'gas': 2954.4,
               'oil': 122.90000000000002,
               'solar': 5.744,
               'unknown': 15.52,
               'wind': 132.889},
  'datetime': datetime.datetime(2020, 1, 7, 9, 0, tzinfo=tzfile('/usr/share/zoneinfo/Australia/Perth')),
  'production': {'coal': 925.419,
                 'gas': 761.9850000000001,
                 'oil': 0.0,
                 'solar': 293.486,
                 'unknown': 9.276,
                 'wind': 157.929},
  'source': 'wa.aemo.com.au, pv-map.apvi.org.au',
  'storage': {},
  'zoneKey': 'AUS-WA'}]

[robertahunt]

Looks good :)