test: delete empty parameters

Delete empty parameters from Makefile_am.  The
openbmc libraries do not presently fill out those
values, only CFLAGS and LIBS.

Change-Id: Ie0171b83abcd943c9ef47d3917cb7691440d2fdb
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 70b72c7..20ddf2f 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,8 +1,6 @@
 AM_CPPFLAGS = \
     -I$(top_srcdir) \
-    $(PTHREAD_CPPFLAGS) \
-    $(SDBUSPLUS_CPPFLAGS) \
-    $(PHOSPHOR_DBUS_INTERFACES_CPPFLAGS)
+    $(PTHREAD_CPPFLAGS)
 
 AM_CFLAGS = \
     $(PTHREAD_CFLAGS) \
@@ -11,9 +9,7 @@
     $(PHOSPHOR_LOGGING_CFLAGS)
 
 AM_CXXFLAGS = \
-    $(PTHREAD_CXXFLAGS) \
-    $(SDBUSPLUS_CXXFLAGS) \
-    $(PHOSPHOR_DBUS_INTERFACES_CXXFLAGS)
+    $(PTHREAD_CXXFLAGS)
 
 AM_LDFLAGS = \
     -lstdc++fs \