remove redundant conversion

[ucwong]

No description provided.

[codecov]

Codecov Report

Merging #837 (a05c092) into master (a7b7050) will increase coverage by 0.02%.
The diff coverage is 36.84%.

@@            Coverage Diff             @@
##           master     #837      +/-   ##
==========================================
+ Coverage   49.10%   49.13%   +0.02%     
==========================================
  Files         418      418              
  Lines       47753    47748       -5     
==========================================
+ Hits        23451    23461      +10     
+ Misses      22248    22235      -13     
+ Partials     2054     2052       -2     

Impacted Files	Coverage Δ
core/headerchain.go	20.25% <0.00%> (+0.08%)	⬆️
core/state/statedb.go	50.25% <0.00%> (ø)
core/vm/cvm.go	15.87% <0.00%> (ø)
crypto/bls12381/g1.go	85.15% <0.00%> (+0.37%)	⬆️
crypto/bls12381/g2.go	84.36% <0.00%> (+0.34%)	⬆️
p2p/nat/nat.go	9.87% <0.00%> (+0.12%)	⬆️
params/version.go	36.84% <ø> (ø)
core/vm/instructions.go	19.76% <25.00%> (ø)
core/vm/gas_table.go	11.38% <50.00%> (ø)
accounts/keystore/passphrase.go	59.14% <100.00%> (ø)
... and 14 more