Update retention policy before saving database

[otoolep]

Without this change, new shard group information is not persisted in the
metastore and only when the next database-save took place would this
update be persisted. If the server shutdown before the update, the new
shard group would be lost.

[otoolep]

@benbjohnson

[otoolep]

Green build.

[otoolep]

I have updated the unit tests so it explicitly tests that shard groups are persisted to disk after a restart. With this change in place, I am now seeing this failure:

--- FAIL: TestServer_CreateShardGroupIfNotExist (1.15s)
panic: open: load: cannot open shard store: id=1, err=timeout [recovered]
        panic: open: load: cannot open shard store: id=1, err=timeout

goroutine 6 [running]:
testing.func·006()
        /home/philip/.gvm/gos/go1.4/src/testing/testing.go:441 +0x181
github.com/influxdb/influxdb_test.(*Server).Restart(0xc208044060)
        /home/philip/Dropbox/repos/influxdb/src/github.com/influxdb/influxdb/server_test.go:1132 +0x23a
github.com/influxdb/influxdb_test.TestServer_CreateShardGroupIfNotExist(0xc208060090)
        /home/philip/Dropbox/repos/influxdb/src/github.com/influxdb/influxdb/server_test.go:875 +0x370
testing.tRunner(0xc208060090, 0xa74470)
        /home/philip/.gvm/gos/go1.4/src/testing/testing.go:447 +0xbf
created by testing.RunTests
        /home/philip/.gvm/gos/go1.4/src/testing/testing.go:555 +0xa8b

goroutine 1 [chan receive]:
testing.RunTests(0x92f3f0, 0xa740e0, 0x30, 0x30, 0xa77c01)
        /home/philip/.gvm/gos/go1.4/src/testing/testing.go:556 +0xad6
testing.(*M).Run(0xc2080462d0, 0xa7f0a0)
        /home/philip/.gvm/gos/go1.4/src/testing/testing.go:485 +0x6c
main.main()
        github.com/influxdb/influxdb/_test/_testmain.go:148 +0x1d5

goroutine 5 [chan receive]:
code.google.com/p/log4go.ConsoleLogWriter.run(0xc20805c060, 0x7f95e0082e98, 0xc208044008)
        /home/philip/Dropbox/repos/influxdb/src/code.google.com/p/log4go/termlog.go:27 +0x7a
created by code.google.com/p/log4go.NewConsoleLogWriter
        /home/philip/Dropbox/repos/influxdb/src/code.google.com/p/log4go/termlog.go:19 +0x6b

goroutine 7 [select]:
github.com/influxdb/influxdb.(*Server).processor(0xc20805e500, 0x7f95e0083310, 0xc208034600, 0xc20805c360)
        /home/philip/Dropbox/repos/influxdb/src/github.com/influxdb/influxdb/server.go:2486 +0x5c8
created by github.com/influxdb/influxdb.(*Server).setClient
        /home/philip/Dropbox/repos/influxdb/src/github.com/influxdb/influxdb/server.go:319 +0x132
exit status 2
FAIL    github.com/influxdb/influxdb    1.158s
~/Dropbox/repos/influxdb/src/github.com/influxdb/influxdb (persist_policies)$ git add -p
diff --git a/server_test.go b/server_test.go
index b947841..5efbd06 100644

so this change may have brought out something else.

[benbjohnson]

The shards aren't being closed in Server.Close(). Fixed: e417852

[otoolep]

Shipt it from @benbjohnson