Send dmidecode errors to /dev/null in the virtual fact

When run as a non-root user, facter would always spew "/dev/mem:
Permission denied" because it called dmidecode without redirecting
stderr.

This was filed upstream as FACT-86¹.  It's unclear what is insufficient
about this method, but failing tests that are not visible aren't as much
of a concern to me as clearly useless output on every run of the
command.

¹ https://tickets.puppetlabs.com/browse/FACT-86

facter-1.7.4-dmidecode-drop-stderr.patch

@@ -0,0 +1,12 @@
+diff -up facter-1.7.4/lib/facter/virtual.rb.dmidecode-drop-stderr facter-1.7.4/lib/facter/virtual.rb
+--- facter-1.7.4/lib/facter/virtual.rb.dmidecode-drop-stderr	2013-12-17 15:23:22.000000000 -0500
++++ facter-1.7.4/lib/facter/virtual.rb	2014-01-28 18:28:27.604949053 -0500
+@@ -133,7 +133,7 @@ Facter.add("virtual") do
+     end
+ 
+     # Parse dmidecode
+-    output = Facter::Util::Resolution.exec('dmidecode')
++    output = Facter::Util::Resolution.exec('dmidecode 2>/dev/null')
+     if output
+       lines = output.split("\n")
+       next "parallels"  if lines.any? {|l| l =~ /Parallels/ }

facter.spec

@@ -28,6 +28,8 @@ License:        ASL 2.0
 URL:            https://puppetlabs.com/%{name}
 Source0:        https://downloads.puppetlabs.com/%{name}/%{name}-%{version}.tar.gz
 Source1:        https://downloads.puppetlabs.com/%{name}/%{name}-%{version}.tar.gz.asc
+# https://tickets.puppetlabs.com/browse/FACT-86
+Patch0:         facter-1.7.4-dmidecode-drop-stderr.patch
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  ruby >= 1.8.1
@@ -69,6 +71,8 @@ key off the values returned by facts.
 
 %prep
 %setup -q
+%patch0 -p1 -b .dmidecode-drop-stderr
+
 
 %build
 # Nothing to build
@@ -118,6 +122,7 @@ rspec spec
 * Tue Jan 28 2014 Todd Zullinger <tmz@pobox.com> - 1.7.4-1
 - Update to 1.7.4
 - Create /etc/facter/facts.d for external facts
+- Send dmiddecode errors to /dev/null in the virtual fact (FACT-86)
 
 * Tue Oct 8 2013 Sam Kottler <skottler@fedoraproject.org> - 1.7.3-1
 - Update to 1.7.3 (BZ #1016817)