build: fix commit that changed option for installing client

Without this patch the option --enable-demo-clients-install does not
install the client demos.

configure.ac

@@ -462,8 +462,8 @@ AC_DEFINE_UNQUOTED([WESTON_SHELL_CLIENT], ["$WESTON_SHELL_CLIENT"],
 AC_ARG_ENABLE(demo-clients-install,
               AS_HELP_STRING([--enable-demo-clients-install],
                              [Install demo clients built with weston]),,
-              install_demo_clients=no)
-AM_CONDITIONAL(INSTALL_DEMO_CLIENTS, [test "install_demo_clients" = "xyes"])
+			     enable_demo_clients_install=no)
+AM_CONDITIONAL(INSTALL_DEMO_CLIENTS, [test "x$enable_demo_clients_install" = "xyes"])
 
 PKG_CHECK_MODULES(LCMS, lcms2,
                   [have_lcms=yes], [have_lcms=no])
@@ -534,7 +534,7 @@ AC_MSG_RESULT([
 	Build Simple Clients		${enable_simple_clients}
 	Build Simple EGL Clients	${enable_simple_egl_clients}
 
-	Install Demo Clients		${install_demo_clients}
+	Install Demo Clients		${enable_demo_clients_install}
 
 	Colord Support			${have_colord}
 	GLU Support			${have_glu}