Fixed static analyzer warnings on API missuse

MacPass/MPDocument+Autotype.m

@@ -32,7 +32,7 @@
 
 + (BOOL)isCandidateForMalformedAutotype:(id)item {
   
-  NSString *keystrokeSequence;
+  NSString *keystrokeSequence = @"";
   if([item isKindOfClass:[KPKEntry class]] && ![((KPKEntry *)item).autotype hasDefaultKeystrokeSequence]) {
     keystrokeSequence = ((KPKEntry *)item).autotype.defaultKeystrokeSequence;
   }

MacPass/MPFixAutotypeWindowController.m

@@ -119,6 +119,10 @@ NSString *const kMPIconCell = @"IconCell";
     association = item;
   }
   
+  if(nil == entry || nil == group || nil == association) {
+    return nil;
+  }
+  
   if([[tableColumn identifier] isEqualToString:kMPTitleCell]) {
     if(entry) {
       return entry.title;