Fix db.RepeatDeadlocked

[Jogo27]

RepeatDeadlocked is certainly the culprit of the MaxConnection bug.

goroutine 892 [select, 9 minutes]:
database/sql.(*DB).conn(0xc00007b860, 0x825380, 0xc000016088, 0x1, 0x0, 0x0, 0x2)
	/usr/lib/go/src/database/sql/sql.go:1242 +0x846
database/sql.(*DB).begin(0xc00007b860, 0x825380, 0xc000016088, 0x0, 0x1, 0x0, 0x0, 0xc000406a78)
	/usr/lib/go/src/database/sql/sql.go:1745 +0x4f
database/sql.(*DB).BeginTx(0xc00007b860, 0x825380, 0xc000016088, 0x0, 0xc000406a50, 0x7350e0, 0xc00022b260)
	/usr/lib/go/src/database/sql/sql.go:1727 +0x89
github.com/JBoudou/Itero/db.RepeatDeadlocked.func2(0x825380, 0xc000016088, 0x0, 0x7cffe0, 0xc0001e1ba7, 0xc0001e1da8)
	/home/jogo/itero/db/database.go:164 +0x67
github.com/JBoudou/Itero/db.RepeatDeadlocked(0x825380, 0xc000016088, 0x0, 0xc0001e1da8)
	/home/jogo/itero/db/database.go:188 +0x66
github.com/JBoudou/Itero/main.UninominalVoteHandler(0x825380, 0xc000016088, 0x8256c0, 0xc00028a170, 0xc000308230)
	/home/jogo/itero/main/univote.go:101 +0x5ed
github.com/JBoudou/Itero/server.HandlerFunc.Handle(0x7d0190, 0x825380, 0xc000016088, 0x8256c0, 0xc00028a170, 0xc000308230)
	/home/jogo/itero/server/handler.go:48 +0x58
github.com/JBoudou/Itero/server.HandlerWrapper.Exec(0x7afd88, 0x7, 0x81f360, 0x7d0190, 0x825380, 0xc000016088, 0x8256c0, 0xc00028a170, 0xc000308230)
	/home/jogo/itero/server/handler.go:87 +0xb8
github.com/JBoudou/Itero/server/servertest.Run.func1(0xc000389800)
	/home/jogo/itero/server/servertest/servertest.go:171 +0x296
testing.tRunner(0xc000389800, 0xc00032e750)
	/usr/lib/go/src/testing/testing.go:1123 +0xef
created by testing.(*T).Run
	/usr/lib/go/src/testing/testing.go:1168 +0x2b3

[Jogo27]

There is no error here, just a possibly infinite loop to be fixed some day.