Make Errno::EADDRINUSE not print a stack trace

lib/nanoc/cli/error_handler.rb

@@ -64,13 +64,16 @@ def handle_while(&_block)
 
       # Run
       yield
-    rescue Nanoc::Int::Errors::GenericTrivial => e
-      $stderr.puts "Error: #{e.message}"
-      exit(1)
     rescue Interrupt
       exit(1)
     rescue StandardError, ScriptError => e
-      print_error(e)
+      if trivial?(e)
+        $stderr.puts "Error: #{e.message}"
+        resolution = resolution_for(e)
+        $stderr.puts resolution if resolution
+      else
+        print_error(e)
+      end
       exit(1)
     end
 
@@ -191,6 +194,15 @@ def gems_and_versions
       'w3c_validators' => 'w3c_validators',
     }.freeze
 
+    def trivial?(error)
+      case error
+      when Nanoc::Int::Errors::GenericTrivial, Errno::EADDRINUSE
+        true
+      else
+        false
+      end
+    end
+
     # Attempts to find a resolution for the given error, or nil if no
     # resolution can be automatically obtained.
     #