add curl as dependency for deepsea package

[denisok]

Description of Issue/Question

There might be systems where curl is not installed.

Setup

vagrant-ceph with custom box.

Steps to Reproduce Issue

admin:/usr/share/grafana # grafana-server                                                               
Grafana-server Init Failed: Could not find config defaults, make sure homepath command line parameter is
set or working directory is homepath                                                                    
admin:/usr/share/grafana # ls -la /var/log/grafana/                                                     
total 0                                                                                                 
drwxr-x--- 1 grafana grafana   0 Oct 18  2017 .                                                         
drwxr-xr-x 1 root    root    248 Apr  2 14:29 ..                                                        
admin:/usr/share/grafana # grafana-server -homepath /usr/share/grafana -config /etc/grafana/grafana.ini 
pidfile /var/run/grafana                                                                                
Grafana-server Init Failed: Could not find config defaults, make sure homepath command line parameter is
set or working directory is homepath                                                                    

Versions Report

salt-run deepsea.version
0.8.9+git.0.c638bee79