Give a better error on a release failure case

If you don't have `ronn` installed, the `man:check` task will fail but
it won't let you know the exact reason.

1 files changed, 1 insertions, 0 deletions

diff --git a/Rakefile b/Rakefile
index 36d313d177..ef673ba38a 100644
--- a/Rakefile
+++ b/Rakefile
@@ -187,6 +187,7 @@ namespace :man do
       Spec::Rubygems.gem_require("ronn")
     rescue Gem::LoadError => e
       task(:build) { abort "We couln't activate ronn (#{e.requirement}). Try `gem install ronn:'#{e.requirement}'` to be able to build the help pages" }
+      task(:check) { abort "We couln't activate ronn (#{e.requirement}). Try `gem install ronn:'#{e.requirement}'` to be able to build the help pages" }
     else
       directory "man"