Fix calendar crash

[rivera-ernesto]

Related to #216 where...

[rivera-ernesto]

A NSInvalidArgumentException was being rised. Only possible cause a bad logMessage->timestamp.

[bpoplauschi]

@rivera-ernesto Your fix looks legit, so I'll merge it. But I'm not sure if that is the only cause. If we look at #216, there are several flavours of crashes:

2014-02-11 21:03:59.849 Sparkle Test App[17768:3903] *** -[NSAutoCalendar class]: message sent to deallocated instance 0x10036b690

Fatal Exception: NSInvalidArgumentException
-[BKSSignal components:fromDate:]: unrecognized selector sent to instance 0x156c3830

Another potential issues would be: logMessage->timestamp has a poor mem mgm, gets deallocated and

• if no other object is allocated in that area so we get the message sent to deallocated instance
• if another object is allocated there, we get the unrecognized selector sent to instance

[rivera-ernesto]

Another potential issues would be: logMessage->timestamp has a poor mem mgm, gets deallocated and

• if no other object is allocated in that area so we get the message sent to deallocated instance
• if another object is allocated there, we get the unrecognized selector sent to instance

Right but probably for those cases the fixes should go to DDLogMessage.