Reset the reason when task retry

[rf-guo]

No description provided.

[codecov]

Codecov Report

Merging #936 into dev will decrease coverage by 0.03%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##                dev     #936      +/-   ##
============================================
- Coverage     62.04%   62.01%   -0.04%     
+ Complexity     2627     2626       -1     
============================================
  Files           239      239              
  Lines         13045    13046       +1     
  Branches       1288     1288              
============================================
- Hits           8094     8090       -4     
- Misses         4227     4232       +5     
  Partials        724      724

Impacted Files	Coverage Δ	Complexity Δ
...tflix/conductor/core/execution/DeciderService.java	85.32% <100%> (+0.05%)	96 <0> (ø)	⬇️
.../java/com/netflix/conductor/service/Lifecycle.java	30% <0%> (-30%)	2% <0%> (-1%)
.../com/netflix/conductor/grpc/server/GRPCServer.java	78.57% <0%> (-14.29%)	4% <0%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5b8b614...aff23d5. Read the comment docs.

[coveralls]

Pull Request Test Coverage Report for Build 2246

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 5 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.04%) to 67.592%

---

Files with Coverage Reduction	New Missed Lines	%
grpc-server/src/main/java/com/netflix/conductor/grpc/server/GRPCServer.java	2	85.71%
core/src/main/java/com/netflix/conductor/service/Lifecycle.java	3	30.0%

Totals
Change from base Build 2240:	-0.04%
Covered Lines:	8818
Relevant Lines:	13046

---

💛 - Coveralls

[cyzhao]

Good catch, but set it to null instead.