Do not distribute tinytest_demo.c in the tarball

src/test/Makefile.am

@@ -29,5 +29,3 @@ test_LDADD = ../or/libtor.a ../common/libor.a ../common/libor-crypto.a \
 	-lz -lm -levent -lssl -lcrypto @TOR_LIB_WS32@ @TOR_LIB_GDI@
 
 noinst_HEADERS = tinytest.h tinytest_macros.h
-
-EXTRA_DIST = tinytest_demo.c