Port reorder install instructions

Reorder the install pm2 step to be after the npm install step in the
instructions.  This is necessary to avoid npm creating some files in the
home directory owned as root and then failing the npm install step
because of this.

This is a port of c25bf23.

CHANGELOG.md

@@ -39,6 +39,8 @@ Version 1.2.2
   to the current one in researchSync.
 - Fixed crash in researchSync when modded technologies are present only on some
   nodes.
+- Reordered install instructions to avoid problem with npm creating files owned
+  by root in the home directory.
 
 
 Version 1.2.1

README.md

@@ -101,7 +101,6 @@ Master and all slaves:
 
     sudo curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
     sudo apt install -y nodejs python-dev git wget curl tar build-essential
-    sudo npm install pm2 -g
     git clone -b 1.2.x https://github.com/clusterio/factorioClusterio.git
     cd factorioClusterio
     curl -o factorio.tar.gz -L https://www.factorio.com/get-download/latest/headless/linux64
@@ -110,8 +109,11 @@ Master and all slaves:
     cp config.json.dist config.json
     node ./lib/npmPostinstall.js
 
+downloads and installs nodejs, git and clusterio. To specify a version, change "latest" in the link to a version number like 0.14.21.
 
-downloads and installs nodejs, pm2, git and clusterio. To specify a version, change "latest" in the link to a version number like 0.14.21.
+Optional step (if you want to use pm2):
+
+    sudo npm install pm2 -g
 
 Now you need to edit the `config.json` file. If you skip this step nothing will work.
 Pretty much all the blank fields should be filled in, except on the master where a few can be omitted.