Also use older node-gyp for electron builds

Author: murgatroid99

tools/release/kokoro-electron.bat

@@ -22,7 +22,7 @@ call nvm use 10
 
 call npm install -g npm
 @rem https://github.com/mapbox/node-pre-gyp/issues/362
-call npm install -g node-gyp
+call npm install -g node-gyp@4
 
 cd /d %~dp0
 cd ..\..

tools/release/kokoro-electron.sh

@@ -21,7 +21,7 @@ nvm install 10
 nvm use 10
 npm install -g npm
 # https://github.com/mapbox/node-pre-gyp/issues/362
-npm install -g node-gyp
+npm install -g node-gyp@4
 
 set -ex
 cd $(dirname $0)/../..