Check for an empty executable passed into the accelerate plugin

This was breaking at least the script module, so it would seem best
to check for it and set it to the default executable value

utilities/accelerate

@@ -217,7 +217,7 @@ class ThreadedTCPRequestHandler(SocketServer.BaseRequestHandler):
         if 'executable' not in data:
             return dict(failed=True, msg='internal error: executable is required')
 
-        log("executing: %s" % data['cmd'])
+        #log("executing: %s" % data['cmd'])
         rc, stdout, stderr = self.server.module.run_command(data['cmd'], executable=data['executable'], close_fds=True)
         if stdout is None:
             stdout = ''
@@ -306,7 +306,7 @@ class ThreadedTCPRequestHandler(SocketServer.BaseRequestHandler):
             log("failed to put the file: %s" % tb)
             return dict(failed=True, stdout="Could not write the file")
         finally:
-            log("wrote %d bytes" % bytes)
+            #log("wrote %d bytes" % bytes)
             out_fd.close()
 
         if final_path: