always set our rails root to our root

this works fine when calling any framework binaries
from their path as CWD. if you call tehm from another path
you will get an incorrect root which can cause certain things to load
incorrectly

Signed-off-by: David Maloney <[email protected]>

Author: David Maloney

lib/metasploit/framework/common_engine.rb

@@ -23,6 +23,7 @@ module Metasploit::Framework::CommonEngine
       Encoding.default_internal = encoding
     end
 
+    config.root = Msf::Config::install_root
     config.paths.add 'data/meterpreter', glob: '**/ext_*'
     config.paths.add 'modules'