The git clone does not create the docs folder, so this fails:
```
/Stage[main]/Icingaweb2::Initialize/Exec[create db scheme]/returns: sh: /usr/share/doc/icingaweb2/schema/mysql.schema.sql: No such file or directory
==> default: Error: mysql --defaults-file='/root/.my.cnf' icingaweb2 < /usr/share/doc/icingaweb2/schema/mysql.schema.sql returned 1 instead of one of [0]
```
This checks if the user is using the git installation method, then changes to the location of the correct schema.
Also adds spec to check this logic
