Suggest feature is not working for non socket connections

[albig]

I use the default setup in Debian 8 which is redis 2.8 and I found your munin plugin. Thanks for sharing!

Unfortunately the suggest feature doesn't work in my setup. Two errors occure:

1. The script fails as the comparison is not valid in line 9 (variable ip_socket is empty)
2. The suggestion is invalid. Instead of "127.0.0.1_6379" the suggest returns "-h 127.0.0.1_-p 6379"

Bad suggestion: -h 127.0.0.1_-p 6379

I'll provide an patch for both in a minute.