Prevent inadvertently repeated callbacks in ProtocolProxy

[chrismayer]

This PR is supposed to fix the FeatureStore issues (ExtJS 5) documented in #378.

As discussed in #378 this fixes issue 1.) and can be used as base for further development to fix issue 2.)

[chrismayer]

Is it possible that switching the call order of setCompleted and setSuccessful will already fix this?
Without the optional true to call setCompleted (Ext 5) from setSuccessful it should be safe.

Hey @bentrm thanks for this suggestion. I gave it a shot and it works. Correcting the execution order also solves the problem and should be more safe. I corrected the commit.

[marcjansen]

Now that's a nice commit/diff.

Thanks to both of you. Please merge, @chrismayer

[chrismayer]

Thanks for your review @marcjansen but this is still work in progress since the second part of the fix, which is more tricky, is still to do. As said in #378 I fear that this is deeply settled somewhere in the ExtJS 'proxy-/reader-world'.

[marcjansen]

You decide, @chrismayer

[bentrm]

@chrismayer, I think this should be merged as it solves the isolated issue of inadvertently repeated callbacks. It would make it easier for others to tackle the remaining issue described in #378 in a separate PR as well.

[chrismayer]

Hi @bentrm,
I agree that we can interpret the inadvertently repeated callbacks as a single issue. I adapted the title of this PR and I will merge this now.

Thank you all for your input.