Deprecated File.exists? call used by symbiosis-httpd-configure in Stretch

[andrewladlow]

Running symbiosis-httpd-configure -vdf returns a deprecated File.exists? warning, as per:

root@blank:~# symbiosis-httpd-configure -vdf
Configuration: blank.default.aladlow.uk0.bigv.io.conf
	Forcing re-creation of configuration due to --force.
/usr/lib/ruby/vendor_ruby/symbiosis/config_file.rb:138: warning: File.exists? is a deprecated name, use File.exist? instead
	Syntax OK
Configuration: zz-mass-hosting.conf
	Forcing re-creation of configuration due to --force.
/usr/lib/ruby/vendor_ruby/symbiosis/config_file.rb:138: warning: File.exists? is a deprecated name, use File.exist? instead
	Syntax OK
Configuration: zz-mass-hosting.ssl.conf
	Forcing re-creation of configuration due to --force.
/usr/lib/ruby/vendor_ruby/symbiosis/config_file.rb:138: warning: File.exists? is a deprecated name, use File.exist? instead
	Syntax OK

[jamielinux]

Fixed by 6fa0cad