bitbake: bitbake-diffsigs: Fix runtime error when no arguments are given

If bitbake-diffsigs is run without arguments it will error:

    Traceback (most recent call last):
      File "./bin/bitbake-diffsigs", line 121, in <module>
        if output:
    NameError: name 'output' is not defined

Fix this by moving the check for output into the inner else-clause.

(Bitbake rev: 7d3545a66863ad7183a7650b2af57eee091c45ae)

Signed-off-by: Jacob Kroon <jacob.kroon@mikrodidakt.se>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/bin/bitbake-diffsigs

@@ -118,5 +118,5 @@ else:
             logger.error('Invalid signature data - ensure you are specifying sigdata/siginfo files')
             sys.exit(1)
 
-    if output:
-        print '\n'.join(output)
+        if output:
+            print '\n'.join(output)