Update staticcheck version and fix all warnings (#1381)

hack/travis-kube-setup.sh

@@ -14,12 +14,12 @@ then
 fi
 
 # Get staticcheck
-STATICCHECK_VERSION=2019.1.1
-if [ ! -f $TOOL_DIR/staticcheck ]
+STATICCHECK_VERSION=2019.2.3
+if [ ! -f $TOOL_DIR/staticcheck ] || (staticcheck -version | grep -v $STATICCHECK_VERSION)
 then
-    curl -LO https://github.com/dominikh/go-tools/releases/download/${STATICCHECK_VERSION}/staticcheck_linux_amd64
-    chmod +x staticcheck_linux_amd64
-    mv staticcheck_linux_amd64 $TOOL_DIR/staticcheck
+    curl -LO https://github.com/dominikh/go-tools/releases/download/${STATICCHECK_VERSION}/staticcheck_linux_amd64.tar.gz
+    tar xzvf staticcheck_linux_amd64.tar.gz
+    mv staticcheck/staticcheck $TOOL_DIR/staticcheck
 fi
 
 K8SCLI_DIR=$HOME/k8scli

hack/verify-staticcheck.sh

@@ -6,12 +6,4 @@ set -o pipefail
 
 ROOT=`realpath $(dirname $0)/..`
 
-# Currently here only lists the packages that already addressed all warnings for gradual code repair.
-# That means we don't allow adding new warnings to any of package in list. And eventually, the
-# list will be replaced by find command.
-declare -a pkgs=("pkg/builder" "pkg/builder" "pkg/crd" "pkg/logger" "pkg/buildermgr" "pkg/fission-cli" "cmd/fission-cli")
-
-for pkg in "${pkgs[@]}"
-do
-    find ${ROOT}/${pkg} -type d |grep -v influxdb | xargs -I@ staticcheck @
-done
+go list ./...| grep -v vendor | grep -v "examples" | grep -v "demos" | xargs -I@ staticcheck @