Database voodoo so sp export doesn't lock up db

Trying two tricks to avoid locking source civi and drupal tables
for insert during large INSERT...SELECT statements.  First, using
temp (unreplicated) tables as the targets of any selects from civi
tables, and second, setting transaction isolation level to read
uncommitted.

Change-Id: I83da6c47c5460544e7378f9c8a45ced984bec59b
Merge branch 'master' into deploy

b1aeb5b Database voodoo so sp export doesn't lock up db

Change-Id: I9e5174ccd1f2f1a88e91f87e1546a3f617627d5c