Improvements in the FAQ (persistence partitions and bootlocal.sh)

[Vrakfall]

Adds some lines to the doc/FAQ.md

-Adds that a default persistence partition is made by the b2d ISO image
-Adds that 2 persistence partitions can't have the same name but
different labels

-Adds that /var/lib/boot2docker/bootlocal.sh script mus be in /bin/sh

I find that it was needed to explain this to the new users. I took many hours to figure it out that /var/lib/boot2docker/bootlocal.sh cannot be writen in bash.

Excuse me for my typos, and please double check the spelling because I'm not a native English speaker.

[Vrakfall]

Hi, any update ?

[matthughes]

I like what you added, but think we could have more docs here.

1. I get that bootlocal.sh/bootsync.sh live in /var/lib/boot2docker/ but how do I get the files there? Is the only way to ssh and manually edit them? I'd love to put those files in ~/.boot2docker on my host and have them auto-sync when I init boot2docker.

2. Still confused about when each of these scripts run. Does bootlocal.sh run before or after bootsync.sh?