Fix various small housekeeping issues

[ksclarke]

Includes several small housekeeping type things:

• Cleans up build artifacts left in $HOME by using /tmp as a scratch space instead
• Adds noninteractive build flag to other scripts too, not just bootstrap.sh
• Fixes what looks like a copy paste error
• Sets quiet flag on wget(s) that didn't already have it
• Resets permission of the .drush directory after the final drush run so the .cache is owned by the 'vagrant' user instead of 'root'

[ruebot]

Testing build now...

[ruebot]

Good to go.

Thanks for finding and fixing my bad copypasta too!