Installation Guide - Standardize configuration key formatting

[Matt Kassawara]

I noticed some inconsistencies with configuration key formatting throughout the installation guide. I recommend using "key = value" rather than "key=value" to increase clarity.

[Stephen Gordon (sgordon)]

As per a similar bug either will work but we should pick one and stick with it. What to the project sample configs use?

[Phil Hopkins (phil-hopkins-a)]

They use both, many nova configs don't use the space and neutron one do. It really varies and I also don't like it. We need some consistency.

[Andreas Jaeger (jaegerandi)]

Updated wiki page to document this:
https://wiki.openstack.org/wiki/Documentation/Conventions#Code_or_data_.28block.29

[Andreas Jaeger (jaegerandi)]

I think this is done already for the Install Guide. A quick grep does not show anything relevant.