setup.py: don't use exact version paho-mqtt
The thing is that in distribution (in this case OpenWrt / TurrisOS), there is an issue that anyone with commit access can backport/cherry-pick updates from master (dev) branch to stable branch.
Let's give an example: reForis wants to use paho-mqtt with version 1.5.0, but in OpenWrt there is version 1.4.0. However, compilation success and we will know it once we try to run updated reForis that it shows 500 Internal Error and by enabling lighttpd error log we can see:
pkg_resources.DistributionNotFound: The 'paho-mqtt==1.5.0' distribution was not found and is required by reforis
There are two solutions:
- remove pinning to specific versions (that's what we prefer) This is similar to 714ffc77.
- add pinned versions to minimal versions (e.g. >=) This has its own advantages and disadvantages. I mean that you were using some features from new versions of dependencies and we will dont know it and reForis at least run, but smth is broken and this has solution that you will let us know that we will update it to some version in distribution