Compilation errors

[Flavio Junqueira]

I'm getting a couple of errors that are trivial to fix in master, but I don't 
know if there is a jira for them already:

s4/s4-core/src/main/java/io/s4/ft/DefaultFileSystemStateStorage.java:54: cannot 
find symbol
symbol  : variable LOG
location: class io.s4.ft.DefaultFileSystemStateStorage
                LOG.warn("Interrupted while waiting on incoming queue.", e);
                ^
s4/s4-core/src/main/java/io/s4/ft/DefaultFileSystemStateStorage.java:83: cannot 
find symbol
symbol  : variable callback
location: class io.s4.ft.DefaultFileSystemStateStorage
                callback.storageOperationResult(
                ^
Let me know if I should submit a patch.

-Flavio