Load prerelease plugins if available

CHANGELOG.md

@@ -10,6 +10,7 @@
     host only networking to work even if the VM has multiple NICs. [GH-382]
   - Touch the network configuration file for RedHat so that the `sed` works
     with host only networking. [GH-381]
+  - Load prerelease versions of plugins if available.
 
 ## 0.7.5 (May 16, 2011)
 

lib/vagrant/plugin.rb

@@ -37,7 +37,7 @@ module Vagrant
         # useful for developers.
         specs = Gem::VERSION >= "1.6.0" ? source.latest_specs(true) : source.latest_specs
 
-        source.latest_specs.each do |spec|
+        specs.each do |spec|
           file = nil
           if Gem::VERSION >= "1.8.0"
             file = spec.matches_for_glob("**/vagrant_init.rb").first