auto-update: add process killer for older versions

In order to be able to update smoothly the versions preceding
the merge of patch 5665, we have to kill manually the process
Ring.exe, this patch adds the functions from the NsProcess
plugin for NSIS enabling such comportment.
The buildmachine script have to be modified in order to fetch this dependency

Change-Id: I0760284133413086dc2b36011c6fa7f2b511043a

ring.nsi

@@ -74,6 +74,16 @@ Function LaunchLink
 FunctionEnd
 
 section "install"
+        !addincludedir "../../NsProcess/Include"
+        !addplugindir "../../NsProcess/Plugin"
+        !include "nsProcess.nsh"
+        # Kill all remaining Ring processes
+        ${nsProcess::FindProcess} "Ring.exe" $R0
+        ${If} $R0 == 0
+         ${nsProcess::KillProcess} "Ring.exe" $R0
+        ${EndIf}
+        Sleep 500
+
         # Files for the install directory - to build the installer, these should be in the same directory as the install script (this file)
         setOutPath $INSTDIR
         # Files added here should be removed by the uninstaller (see section "uninstall")