Rewords Networking architecture section

Rewords language to distinguish between process, services and
components. Updates some technical terminology. Various other small
changes throughout.

Change-Id: I6d39b7707a0971251974d41636415d73a18b7bf7
Partial-Bug: #1217503
Fix incorrect nova boot command

nova boot need a positional parameter for server name, but the example
for user guide section of nova boot is wrong, we should fix it.

Note that I also correct the output according to the parameter.

Change-Id: I5f41d5fdd15ea274222e35705002fc56317f4989
Closes-Bug: #1285559
Merge "Rewords Networking architecture section"
Merge "Fix incorrect nova boot command"