Description of problem:
foreman-maintain service can not connect to remote mongodb when pulp configuration contain empty path to a ssl cert.

/etc/pulp/server.conf
...
[database]
name: pulpdb
seeds: <host>:27017
username: pulpuser
password: +FILTERED+
ssl: true
ssl_certfile: 
verify_ssl: false
ca_path: /etc/pki/tls/certs/ca-bundle.crt
unsafe_autoretry: false
...

After 'foreman-maintain service status' /var/log/foreman-maintain/foreman-maintain.log contains:

D, [2019-02-07 23:58:37+0000 #5681] DEBUG -- : Running command scl enable rh-mongodb34 -- mongo -u pulpuser -p [FILTERED] --host <host> --port 27017 --ssl --sslCAFile /etc/pki/tls/certs/ca-bundle.crt 
--sslPEMKeyFile  --eval 'db.version()' pulpdb with stdin nil
D, [2019-02-07 23:58:37+0000 #5681] DEBUG -- : output of the command:
 2019-02-07T23:58:37.429+0000 E NETWORK  [main] cannot read certificate file: --eval error:02001002:system library:fopen:No such file or directory
Failed global initialization: InvalidSSLConfiguration Can not set up PEM key file.
D, [2019-02-07 23:58:37+0000 #5681] DEBUG -- : Mongo version detection failed, choosing from installed versions


Version-Release number of selected component (if applicable):
foreman_maintain (0.2.11)


How reproducible:
always

Steps to Reproduce:
1. Configure Satellite to use remote MongoDB
2. Have ssl_certfile: <empty> in /etc/pulp/server.conf
3. Make sure the remote DB is running

Actual results:
$ foreman-maintain service status
...
rh-mongodb34-mongod is remote and is DOWN.
...

Expected results:
$ foreman-maintain service status
...
rh-mongodb34-mongod is remote and is UP.
...

Additional info:
foreman-maintain also ignores the following parameters that were present in the config: 

verify_ssl: false
unsafe_autoretry: false