Set uuid directly if VM couldn't be found. [GH-725]

This fixes a rare edge case where an exception could actually cause
Vagrant to remove the UUID state of a running VM, "losing" it.

CHANGELOG.md

@@ -17,6 +17,8 @@
   - Unix-style line endings are used properly for guest OS. [GH-727]
   - Retry certain VirtualBox operations, since they intermittently fail.
     [GH-726]
+  - Fix issue where Vagrant would sometimes "lose" a VM if an exception
+    occurred. [GH-725]
 
 ## 0.9.7 (February 9, 2012)
 

lib/vagrant/vm.rb

@@ -131,7 +131,7 @@ module Vagrant
         # Clear the UUID since this VM doesn't exist. Note that this calls
         # back into `reload!` but shouldn't ever result in infinite
         # recursion since `@uuid` will be nil.
-        self.uuid = nil
+        @uuid = nil
       end
     end