logback: revert to 1.0.12

Update of logback from 1.0.12 to 1.1.1 causes the alarmserver to throw this exception.  The same configuration works fine in 1.0.12.

java.lang.NullPointerException
        at ch.qos.logback.core.subst.Parser.T(Parser.java:75)
        at ch.qos.logback.core.subst.Parser.E(Parser.java:50)
        at ch.qos.logback.core.subst.Parser.parse(Parser.java:46)
        at ch.qos.logback.core.subst.NodeToStringTransformer.tokenizeAndParseString(NodeToStringTransformer.java:55)
        at ch.qos.logback.core.subst.NodeToStringTransformer.handleVariable(NodeToStringTransformer.java:96)
        at ch.qos.logback.core.subst.NodeToStringTransformer.compileNode(NodeToStringTransformer.java:72)
        at ch.qos.logback.core.subst.NodeToStringTransformer.transform(NodeToStringTransformer.java:60)
        at ch.qos.logback.core.subst.NodeToStringTransformer.substituteVariable(NodeToStringTransformer.java:48)
        at ch.qos.logback.core.util.OptionHelper.substVars(OptionHelper.java:117)
        at ch.qos.logback.core.joran.spi.InterpretationContext.subst(InterpretationContext.java:159)
        at ch.qos.logback.core.joran.action.NestedBasicPropertyIA.body(NestedBasicPropertyIA.java:87)
        at ch.qos.logback.core.joran.spi.Interpreter.callBodyAction(Interpreter.java:295)
        at ch.qos.logback.core.joran.spi.Interpreter.characters(Interpreter.java:175)
        at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:57)
        at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:149)
        at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:135)
        at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:99)
        at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:76)
        at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:68)
        at org.dcache.alarms.server.LogEntryServerWrapper.startUp(LogEntryServerWrapper.java:181)
        ...

Target: master
Patch: http://rb.dcache.org/r/6719
Require-notes: no
Require-book: no
Acked-by: Paul