Fix hasWritePending in op's callback

[gkubisa]

doc.hasWritePending() should be false in the op's callback after the last operation is complete.

Additionally, checking for this.inflightOp first in this.inflightOp && this.inflightOp.callbacks avoids a TypeError which would happen, if this _otApply failed and caused a hard rollback. Unfortunately, I don't have a test for this situation, as it's a rather obscure edge case.

[coveralls]

Coverage increased (+0.002%) to 96.163% when pulling 3b17141 on Teamwork:fix-hasWritePending-in-op-callback into ea5053b on share:master.

[coveralls]

Coverage increased (+0.002%) to 96.163% when pulling 3b17141 on Teamwork:fix-hasWritePending-in-op-callback into ea5053b on share:master.

[coveralls]

Coverage increased (+0.002%) to 96.163% when pulling 3b17141 on Teamwork:fix-hasWritePending-in-op-callback into ea5053b on share:master.

[coveralls]

Coverage decreased (-0.3%) to 96.212% when pulling e117022 on Teamwork:fix-hasWritePending-in-op-callback into 68bde00 on share:master.

[gkubisa]

@nateps @ericyhwang , could you provide some feedback on this PR, or merge it, if it's all good, please?

[ericyhwang]

Nate from the PR review meeting:

Makes sense. I'll need to read through the rest of the code offline to check a few things [before merging].

[curran]

Suggest to close as stale.