Too many build servers doing background retesting of the same submission

[GoogleCodeExporter]

It looks like when a submission is tested, it now becomes enabled for 
background retesting. And it looks like it is often the case that all build 
servers will offer to retest it. 

If it happens that the submission takes a long time to test, this could take 
all the build servers off line.

We should increase the number of pending build requests when we do a background 
retest, and only retest submissions that have no pending background tests.

Original issue reported on code.google.com by bill.p...@gmail.com on 15 Mar 2012 at 3:52

[GoogleCodeExporter]

Code written and pushed, needs testing

Original comment by bill.p...@gmail.com on 21 Mar 2012 at 3:36

• Changed state: Started