billing: add flag to turn plotting on/off; fix SQL for migration scripts

module: dcache services billing

When running the liquibase changesets on the billing database from 1.9.12+, there may be interference from the plotting thread which runs in a separate thread and already begins to execute queries on non-existent views.  This might actually cause the creation of the additional triggers to hang inside of the liquibase thread.

This version of billing never added the ability to turn plot generation on or off.  We add that capability here, and recommend that plots be turned off when running the upgraded dCache for the first time.

It also came to my attention that a patch fixing some typos in the migration scripts provided in shared/migration was never merged to this branch, so I have included those fixes as well (see http://rb.dcache.org/r/4389, trunk@17253).

Target: 2.2
Patch: http://rb.dcache.org/r/5500/
Merge-req: http://rt.dcache.org/Ticket/Display.html?id=7784
Require-book: no
Require-notes: yes
Acked-by: Tigran

RELEASE NOTES:  Adds ability, via the "generatePlots" property (found in later versions), to turn plotting off or on (on by default).  This is recommended when running the first time, since the plotting thread may interfere with the liquibase migration.  The sql migration scripts (in shared/migration) also had a some typographical problems which have been corrected.

Tested on testbed.
Merge pull request #9 from alrossi/2.2

billing: add flag to turn plotting on/off; fix SQL for migration scripts