core: evohome fails converting non-UTC times

The problem

When a service call is made to evohome.set_zone_override, an hour is added to the duration if the system is in UTC+1.

Environment

Home Assistant release with the issue: 0.105.3
Last working Home Assistant release (if known): N/A (new feature)
Operating environment (Hass.io/Docker/Windows/etc.): N/A
Integration causing this issue: evohome
Link to integration documentation on our website: https://www.home-assistant.io/integrations/evohome

Problem-relevant `configuration.yaml`

Traceback/Error logs

For example, the following call works (note: duration=minutes=10), but is in UTC+0:

2020-02-11 18:52:26 DEBUG (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=evohome, service=set_zone_override, service_data=entity_id=climate.bathroom, setpoint=5.5, duration=minutes=10>

… should result in (setpoint_mode=TemporaryOverride, until=2020-02-11T19:02:26+00:00):

2020-02-11 18:52:29 DEBUG (MainThread) [homeassistant.core] Bus:Handling <Event state_changed[L]: entity_id=climate.bathroom, ... new_state=<state climate.bathroom=off; hvac_modes=['off', 'heat'], min_temp=5.5, max_temp=24.5, preset_modes=['none', 'temporary', 'permanent'], current_temperature=19.7, temperature=5.5, hvac_action=off, preset_mode=temporary, status=setpoints=this_sp_from=2020-02-11T18:00:00+00:00, this_sp_temp=19.5, next_sp_from=2020-02-11T19:10:00+00:00, next_sp_temp=18.5, zone_id=3449703, active_faults=[], setpoint_status=target_heat_temperature=5.5, setpoint_mode=TemporaryOverride, until=2020-02-11T19:02:26+00:00, temperature_status=temperature=19.5, is_available=True, friendly_name=Bathroom, icon=mdi:radiator, supported_features=17 @ 2020-02-11T18:52:29.250006+00:00>>

2020-02-11 18:53:00 DEBUG (MainThread) [homeassistant.core] Bus:Handling <Event state_changed[L]: entity_id=climate.bathroom, ... new_state=<state climate.bathroom=off; hvac_modes=['off', 'heat'], min_temp=5.5, max_temp=24.5, preset_modes=['none', 'temporary', 'permanent'], current_temperature=19.7, temperature=5.5, hvac_action=off, preset_mode=temporary, status=setpoints=this_sp_from=2020-02-11T18:00:00+00:00, this_sp_temp=19.5, next_sp_from=2020-02-11T19:10:00+00:00, next_sp_temp=18.5, zone_id=3449703, active_faults=[], setpoint_status=target_heat_temperature=5.5, setpoint_mode=TemporaryOverride, until=2020-02-11T19:02:00+00:00, temperature_status=temperature=19.5, is_available=True, friendly_name=Bathroom, icon=mdi:radiator, supported_features=17 @ 2020-02-11T18:52:29.250006+00:00>>

… the second entry is because the vendor rounds the time to the nearest minute.