Fix startup plist instructions.

Closes Homebrew/homebrew#16369.

Library/Homebrew/formula_installer.rb

@@ -175,16 +175,12 @@ class FormulaInstaller
     end
 
     if f.plist or keg.plist_installed?
-      if f.plist_startup and false
-        destination = '/Library/LaunchDaemons'
-      else
-        destination = '~/Library/LaunchAgents'
-      end
+      destination = f.plist_startup ? '/Library/LaunchDaemons' \
+                                    : '~/Library/LaunchAgents'
 
       plist_filename = f.plist_path.basename
       plist_link = "#{destination}/#{plist_filename}"
       plist_domain = f.plist_path.basename('.plist')
-      launchctl_load = "launchctl load -w #{plist_link}"
       destination_path = Pathname.new File.expand_path destination
       plist_path = destination_path/plist_filename
       s = []
@@ -192,22 +188,42 @@ class FormulaInstaller
       # we readlink because this path probably doesn't exist since caveats
       # occurs before the link step of installation
       if not (plist_path).file? and not (plist_path).symlink?
-        s << "To have launchd start #{f.name} at login:"
-        s << "    mkdir -p #{destination}" unless destination_path.directory?
-        s << "    ln -sfv #{HOMEBREW_PREFIX}/opt/#{f.name}/*.plist #{destination}" #sudo
+        if f.plist_startup
+          s << "To have launchd start #{f.name} at startup:"
+          s << "    sudo mkdir -p #{destination}" unless destination_path.directory?
+          s << "    sudo cp -fv #{HOMEBREW_PREFIX}/opt/#{f.name}/*.plist #{destination}"
+        else
+          s << "To have launchd start #{f.name} at login:"
+          s << "    mkdir -p #{destination}" unless destination_path.directory?
+          s << "    ln -sfv #{HOMEBREW_PREFIX}/opt/#{f.name}/*.plist #{destination}"
+        end
         s << "Then to load #{f.name} now:"
-        s << "    #{launchctl_load}"
+        if f.plist_startup
+          s << "    sudo launchctl load #{plist_link}"
+        else
+          s << "    launchctl load #{plist_link}"
+        end
         if f.plist_manual
           s << "Or, if you don't want/need launchctl, you can just run:"
           s << "    #{f.plist_manual}"
         end
       elsif Kernel.system "/bin/launchctl list #{plist_domain} &>/dev/null"
         s << "You should reload #{f.name}:"
-        s << "    launchctl unload -w #{plist_link}"
-        s << "    #{launchctl_load}"
+        if f.plist_startup
+          s << "    sudo launchctl unload #{plist_link}"
+          s << "    sudo cp -fv #{HOMEBREW_PREFIX}/opt/#{f.name}/*.plist #{destination}"
+          s << "    sudo launchctl load #{plist_link}"
+        else
+          s << "    launchctl unload #{plist_link}"
+          s << "    launchctl load #{plist_link}"
+        end
       else
         s << "To load #{f.name}:"
-        s << "    #{launchctl_load}"
+        if f.plist_startup
+          s << "    sudo launchctl load #{plist_link}"
+        else
+          s << "    launchctl load #{plist_link}"
+        end
       end
 
       ohai 'Caveats', s