wrap tomcat dpkg command and rex version

Author: h00die

modules/exploits/linux/local/tomcat_ubuntu_log_init_priv_esc.rb

@@ -84,7 +84,7 @@ def catalina
 
   def check
     package = cmd_exec('dpkg -l tomcat[6-8] | grep \'^i\'')
-    if package.nil? || package.empty?
+    if package.nil? || package.empty? || package.include?('not found') # catch dpkg command not found
       return CheckCode::Safe('Unable to execute command to determine installed pacakges')
     end