[submodule]: update submodules sonic-sairedis, sonic-swss-common (#4722)

[sonic-sairedis]
* 322dd01 2020-06-05 | Fix debian/rules makefile: use shell commands instead of dollar replacements (#621) (HEAD -> master, origin/master, origin/HEAD) [Qi Luo]
* 6d55a75 2020-06-04 | Update SAI pointer to 1.6.1 (#620) [Mahesh Maddikayala]
* d6c40e5 2020-06-01 | [MultiDB] use get API to obtain dbid instead of hardcode value (#618) [Dong Zhang]
* bd132ec 2020-06-01 | Add synchronous mode to sairedis library (#617) [Kamil Cudnik]
* 0a77a09 2020-06-01 | [meta] Fix tests to be backward compatible (#619) [Kamil Cudnik]

[sonic-swss-common]
* 35bc01a 2020-06-05 | EVPN VXLAN DB support (#339) (HEAD -> master, origin/master, origin/HEAD) [Rajesh Sankaran]
* 2c7354b 2020-05-30 | Add modifyRedis flag to consumer table object (#344) [Kamil Cudnik]
* 5a32636 2020-05-27 | Fix memory leak in pyext when Selectable is returned to Python (#343) [pavel-shirshov]