Fix ::icinga2::pki::ca for FreeBSD

[bobapple]

Running ::icinga2::pki::ca on FreeBSD (10 and 11) does not work properly.

==> i2freebsd11puppet4: Notice: Compiled catalog for i2freebsd11puppet4.int.netways.de in environment production in 1.30 seconds
==> i2freebsd11puppet4: Error: Could not find command 'icinga2'
==> i2freebsd11puppet4: Error: /Stage[main]/Icinga2::Pki::Ca/Exec[create-icinga2-ca]/returns: change from notrun to 0 failed: Could not find command 'icinga2'
==> i2freebsd11puppet4: Notice: /Stage[main]/Icinga2::Pki::Ca/File[/usr/local/etc/icinga2/pki/ca.crt]: Dependency Exec[create-icinga2-ca] has failures: true

==> i2freebsd11puppet4: Notice: Compiled catalog for i2freebsd11puppet4.int.netways.de in environment production in 1.29 seconds
==> i2freebsd11puppet4: Notice: /Stage[main]/Icinga2::Pki::Ca/Exec[create-icinga2-ca]/returns: executed successfully
==> i2freebsd11puppet4: Error: /Stage[main]/Icinga2::Pki::Ca/File[/usr/local/etc/icinga2/pki/ca.crt]: Could not evaluate: Could not retrieve information from environment production source(s) file:/var/icinga2/ca/ca.crt
==> i2freebsd11puppet4: Notice: /Stage[main]/Icinga2::Pki::Ca/Exec[icinga2 pki create certificate signing request]: Dependency File[/usr/local/etc/icinga2/pki/ca.crt] has failures: true

Currently I can see two issues:

• $path varoable in create-icinga2-ca exec
• $::icinga2::params::ca_dir variable is wrong for freebsd