(boxen#21) Throw error if recovery_message contains '

Previously, if you declared an `osx::recovery_message` resource that
contained an apostrophe/single-quote ('), the exec used to set the
recovery message would fail (because the exec references the message
within single quotes).

This commit will call the fail() function if a recovery_message contains
an apostrophe and alert the user to the failure.  The spec was also updated
and worked for me in 1.8.7 and 1.9.3

manifests/recovery_message.pp

@@ -10,6 +10,15 @@
   $kextdir     = '/System/Library/Extensions'
   $eficachedir = '/System/Library/Caches/com.apple.corestorage/EFILoginLocalizations'
 
+  # The recovery message cannot contain an apostrophe (') because we're passing
+  # it into a single-quoted exec. If it does contain an apostrophe, fail and
+  # alert the user
+  if "'" in $value {
+    fail("Your osx::recovery_message declaration contains an apostrophe ('),",
+         "which will cause the exec used to set the message to fail. Please",
+         "remove the apostrophe and try again. Your message: \"${value}\"")
+  }
+
   # The CoreStorage kext cache needs to be updated so the recovery message
   # is displayed on the FDE pre-boot screen.
   #

spec/defines/recovery_message_spec.rb

@@ -58,4 +58,15 @@
       })
     end
   end
+
+  context 'Given a value with an apostrophe' do
+    let(:title) { "Jack's message with an apostrophe" }
+    let(:error) { "Your osx::recovery_message declaration contains an apostrophe" }
+
+    it do
+      expect {
+        should contain_exec('Set OS X Recovery Message NVRAM Variable')
+      }.to raise_error(Puppet::Error, /#{error}/)
+    end
+  end
 end