sensor: add gpio handle test variation

Add a sensor constructor test where the gpio handle is required.

Change-Id: I05050fb71a6287183ca94f974e965e3f58de9499
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 8573194..2682d45 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -30,5 +30,5 @@
 	$(GPIOPLUS_LIBS) \
 	$(top_builddir)/sensor.o \
 	$(top_builddir)/hwmon.o \
-	$(top_builddir)/gpio_handle.o \
-	env.o
+	env.o \
+	gpio.o