Move error messages to check

Author: OJ

modules/exploits/windows/local/mqac_write.rb

@@ -110,6 +110,7 @@ def open_device
   def check
     handle = open_device
     if handle.nil? || handle == INVALID_HANDLE_VALUE
+      print_error("MSMQ installation not found")
       return Exploit::CheckCode::Safe
     end
     session.railgun.kernel32.CloseHandle(handle)
@@ -119,6 +120,7 @@ def check
     when /windows xp.*service pack 3/i
       return Exploit::CheckCode::Appears
     when /windows xp/i
+      print_error("Incorrect version of Windows XP detected")
       return Exploit::CheckCode::Detected
     else
       return Exploit::CheckCode::Safe
@@ -141,10 +143,7 @@ def exploit
 
     # Running on Windows XP versions that aren't listed in the supported list results
     # in a BSOD and so we should not let that happen.
-    if check != Exploit::CheckCode::Appears
-      print_error("Target machine not supported (incorrect Windows version or missing MSMQ)")
-      return
-    end
+    return unless check == Exploit::CheckCode::Appears
 
     kernel_info = find_sys_base(nil)
     base_addr = 0xffff