The default value of "netboot" was introduced to this configuration
variable as part of commit 93f947c852409af2c56a499428b09ff69ab345a1
in Ocata release.
This patch changes the default value of configuration parameter
'[deploy]/default_boot_option' and devstack variable
'IRONIC_DEFAULT_BOOT_OPTION' to 'local'.
Change-Id: I9bf56a7088281bbe20b8b6c2e47c6ab6559bfea4
Story: #1619339
Task: #10505
6a73f7fdd0