Bugfix: configure: Correctly detect "nothing to build" condition

configure.ac

@@ -839,7 +839,7 @@ else
   AC_MSG_RESULT([no])
 fi
 
-if test x$build_bitcoin_utils$build_bitcoin_libs$build_bitcoind$bitcoin_enable_qt$use_tests = xnononono; then
+if test x$build_bitcoin_utils$build_bitcoin_libs$build_bitcoind$bitcoin_enable_qt$use_tests = xnonononono; then
   AC_MSG_ERROR([No targets! Please specify at least one of: --with-utils --with-libs --with-daemon --with-gui or --enable-tests])
 fi