fix msfbasedir for go_pro

go_pro uses the wrong base director y for starting
up metasploit pro when using the go_pro command
this caused errors

lib/msf/ui/console/command_dispatcher/core.rb

@@ -3006,7 +3006,7 @@ class Core
       print_warning "to start Metasploit Community / Pro."
       return false
     end
-    svc_log = File.expand_path(File.join(msfbase_dir, ".." , "engine", "prosvc_stdout.log"))
+    svc_log = File.expand_path(File.join(ENV['METASPLOIT_ROOT'], "apps" , "pro", "engine", "prosvc_stdout.log"))
     unless ::File.readable_real? svc_log
       print_error "Unable to access log file: #{svc_log}"
       return false
@@ -3041,7 +3041,7 @@ class Core
   end
 
   def start_metasploit_service
-    cmd = File.expand_path(File.join(msfbase_dir, '..', '..', '..', 'scripts', 'start.sh'))
+    cmd = File.expand_path(File.join(ENV['METASPLOIT_ROOT'], 'scripts', 'start.sh'))
     return unless ::File.executable_real? cmd
     %x{#{cmd}}.each_line do |line|
       print_status line.chomp