Fix logic

key? would return false/nil if set to such value, causing us to take
true branch

has_key?("key") will return true, regardless what value key is set,
causing us to take key value branch

lib/oxidized/hook/ciscosparkdiff.rb

@@ -22,7 +22,7 @@ def run_hook(ctx)
     room = CiscoSpark::Room.new(id: cfg.space)
     log "Connected"
 
-    if cfg.diff? ? cfg.diff : true
+    if cfg.has_key?("diff") ? cfg.diff : true
       gitoutput = ctx.node.output.new
       diff = gitoutput.get_diff ctx.node, ctx.node.group, ctx.commitref, nil
       title = ctx.node.name.to_s

lib/oxidized/hook/slackdiff.rb

@@ -21,7 +21,7 @@ def run_hook(ctx)
     client = Slack::Client.new
     client.auth_test
     log "Connected"
-    if cfg.diff? ? cfg.diff : true
+    if cfg.has_key?("diff") ? cfg.diff : true
       gitoutput = ctx.node.output.new
       diff = gitoutput.get_diff ctx.node, ctx.node.group, ctx.commitref, nil
       unless diff == "no diffs"