Makefile.am: Use AM_CPPFLAGS
Since automake 1.13 INCLUDES is depricates and causes a warning
diff --git a/openbsc/src/ipaccess/Makefile.am b/openbsc/src/ipaccess/Makefile.am
index 0b7c2f6..308215b 100644
--- a/openbsc/src/ipaccess/Makefile.am
+++ b/openbsc/src/ipaccess/Makefile.am
@@ -1,4 +1,4 @@
-INCLUDES = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
AM_LDFLAGS = $(COVERAGE_LDFLAGS)
OSMO_LIBS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOABIS_LIBS)