lvm_support: update fact to use no headings

I noticed upgrading that the `lvm_vg_#{vg}_pv` facts dose not use
the `--no-headings` switch like the other facts.

This PR adds the `--no-headings` switch and simplifies the collection

Author: b4ldr

lib/facter/lvm_support.rb

@@ -33,10 +33,13 @@
   Facter.add("lvm_vg_#{i}") { setcode { vg } }
   Facter.add("lvm_vg_#{vg}_pvs") do
     setcode do
-      pvs = Facter::Core::Execution.execute("vgs -o pv_name #{vg} 2>/dev/null", timeout: 30)
+      pvs = Facter::Core::Execution.execute(
+        "vgs -o pv_name --noheadings #{vg} 2>/dev/null",
+        timeout: 30
+      )
       res = nil
       unless pvs.nil?
-        res = pvs.split("\n").select { |l| l =~ %r{^\s+/} }.map(&:strip).sort.join(',')
+        res = pvs.split("\n").map(&:strip).sort.join(',')
       end
       res
     end