update launch.lua to read the hash from the manifest

Author: abstewart

CONTRIBUTING.md

@@ -86,7 +86,7 @@ Note that automatic updates are disabled in Dev Mode.
 
 Sometimes you may need to force Dev mode OFF when running from the dev branch to debug a specific part of Path of Building (e.g. the update system).
 
-To do so [comment out Line 54 to line 58](./src/Launch.lua#L54-L58) of the [Launch.lua](./src/Launch.lua) file:
+To do so [comment out Line 65 to line 69](./src/Launch.lua#L65-L69) of the [Launch.lua](./src/Launch.lua) file:
 ```
 	--if localManXML and not self.versionBranch and not self.versionPlatform then
 	--    -- Looks like a remote manifest, so we're probably running from a repository

src/Launch.lua

@@ -21,6 +21,7 @@ function launch:OnInit()
 	self.versionNumber = "?"
 	self.versionBranch = "?"
 	self.versionPlatform = "?"
+	self.versionCommitHashShort = "?"
 	self.lastUpdateCheck = GetTime()
 	self.subScripts = { }
 	self.startTime = startTime
@@ -47,6 +48,7 @@ function launch:OnInit()
 			if type(node) == "table" then
 				if node.elem == "Version" then
 					self.versionNumber = node.attrib.number
+					self.versionCommitHashShort = node.attrib.hash
 					self.versionBranch = node.attrib.branch
 					self.versionPlatform = node.attrib.platform
 				end