Fix swift-ring-builder for swift 1.8

In some case, there are no spaces before - of the balance in swift 1.8.
The change fix this.

/etc/swift/object.builder, build version 9
32768 partitions, 3.000000 replicas, 1 regions, 3 zones, 9 devices, 200.00 balance
The minimum number of hours before a partition can be reassigned is 24
Devices:    id  region  zone      ip address  port      name weight partitions balance meta
             0     1     1      10.68.0.45  6000       sdd 100.00      32768 200.00
             1     1     2      10.68.0.46  6000       sdd 100.00          0-100.00
...

Change-Id: Ic7757a22ce94e4d51ae11780d4626c90a9ed430f
Merge branch 'swift-1.8-compat' into sileht/cw/master