[KYUUBI-219]Fix NPE in HiveTokenCollector

[yaooqinn]

No description provided.

[codecov]

Codecov Report

Merging #220 into master will not change coverage.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master     #220   +/-   ##
=========================================
  Coverage     82.19%   82.19%           
  Complexity      774      774           
=========================================
  Files            96       96           
  Lines          4128     4128           
  Branches        567      567           
=========================================
  Hits           3393     3393           
  Misses          441      441           
  Partials        294      294

Impacted Files	Coverage Δ	Complexity Δ
...n/kyuubi/session/security/HiveTokenCollector.scala	59.09% <100%> (ø)	0 <0> (ø)	⬇️

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