[submodule] Advance sonic-py-swsssdk pointer

Update sonic-py-swsssdk submodule pointer to include the following:
* e30a1e1 Throw exception when not use swsssdk in UT. ([sonic-net#126](sonic-net/sonic-py-swsssdk#126))

Signed-off-by: dprital <drorp@nvidia.com>