Changes:
Simplify nested complexity
If an if blocks ends with a return statement then remove the else nesting.
Most of the changes has also been reported in golint https://goreportcard.com/report/github.com/ethereum/go-ethereum#golint
# Conflicts:
# cmd/utils/flags.go
# console/bridge.go
# crypto/bls12381/g2.go
# les/benchmark.go
# les/lespay/server/balance.go
# les/lespay/server/balance_tracker.go
# les/lespay/server/prioritypool.go
# les/odr_requests.go
# les/serverpool.go
# les/serverpool_test.go
# p2p/nodestate/nodestate_test.go
# trie/committer.go
86dd1f91dd