fix issue Possible memory leak #219

[lion4ik]

I've fixed this memory leak. Please look through. I would be grateful if you could do it quickly. It affects me on production ((

[codecov-io]

Codecov Report

Merging #220 into RxJava2.x will increase coverage by 1.68%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##           RxJava2.x     #220      +/-   ##
=============================================
+ Coverage      75.94%   77.62%   +1.68%     
=============================================
  Files             10       10              
  Lines            370      371       +1     
  Branches          33       33              
=============================================
+ Hits             281      288       +7     
+ Misses            65       58       -7     
- Partials          24       25       +1

Impacted Files	Coverage Δ
.../strategy/PreLollipopNetworkObservingStrategy.java	66.66% <100%> (+19.79%)	⬆️

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[pwittchen]

Thanks for you PR. The fix looks fine. I'll just test it and I think, it could be merged ASAP.

[pwittchen]

I merged this update, added a missing unit test for bug proof and made tiny refactoring.

Fix will be available in the next release.

Thanks @lion4ik!