(#11276) Checksum files in binary mode

Previously, the puppet module tool would checksum a file in text mode. On
Windows, this would cause the module tool to report that a module had
local changes due to it computing the wrong MD5 checksum (due to File.read
translating '\r\n' to '\n').

This commit changes it to read the file in binary mode instead. This has
no effect on non-Windows platforms.

Author: joshcooper

lib/puppet/module_tool/checksums.rb

@@ -16,7 +16,7 @@ def initialize(path)
 
     # Return checksum for the +Pathname+.
     def checksum(pathname)
-      return Digest::MD5.hexdigest(pathname.read)
+      return Digest::MD5.hexdigest(IO.binread(pathname))
     end
 
     # Return checksums for object's +Pathname+, generate if it's needed.