multi instances of config options kills 2018.3.0 minions

[colin-stubbs]

in particular the 'master_alive_interval' option is written twice in f_defaults.conf at line 98 and and 471

Result is,

2018-04-27 16:32:10,468 [salt.minion :1854][INFO ][49997] Returning information for job: 20180427163158790191
2018-04-27 16:32:11,060 [salt.config :2112][ERROR ][50106] Error parsing configuration file: /etc/salt/minion.d/f_defaults.conf - while constructing a mapping
in "/etc/salt/minion.d/f_defaults.conf", line 19, column 1
found conflicting ID 'master_alive_interval'
in "/etc/salt/minion.d/f_defaults.conf", line 402, column 1
2018-04-27 16:32:11,061 [salt.config :2253][ERROR ][50106] Error parsing configuration file: /etc/salt/minion.d/f_defaults.conf - while constructing a mapping
in "/etc/salt/minion.d/f_defaults.conf", line 19, column 1
found conflicting ID 'master_alive_interval'
in "/etc/salt/minion.d/f_defaults.conf", line 402, column 1
2018-04-27 16:32:12,882 [salt.utils.parsers:1045][WARNING ][50395] Minion received a SIGTERM. Exiting.
2018-04-27 16:32:12,882 [salt.cli.daemons :85 ][INFO ][50395] Shutting down the Salt Minion

Duplicate line writes need to be removed.