tests: Set WESTON_DATA_DIR for tests

Set the env var to override the system data directory so we can run
tests with uninstalled icons.

We don't yet use the code that checks this env var, so make distcheck
will still fail.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

tests/weston-tests-env

@@ -40,6 +40,7 @@ case $TEST_FILE in
 		SHELL_PLUGIN=$MODDIR/ivi-shell.so
 
 		set -x
+		WESTON_DATA_DIR=$abs_top_srcdir/data \
 		WESTON_BUILD_DIR=$abs_builddir \
 		WESTON_TEST_REFERENCE_PATH=$abs_top_srcdir/tests/reference \
 		$WESTON --backend=$MODDIR/$BACKEND \
@@ -53,6 +54,7 @@ case $TEST_FILE in
 		;;
 	*.la|*.so)
 		set -x
+		WESTON_DATA_DIR=$abs_top_srcdir/data \
 		WESTON_BUILD_DIR=$abs_builddir \
 		WESTON_TEST_REFERENCE_PATH=$abs_top_srcdir/tests/reference \
 		$WESTON --backend=$MODDIR/$BACKEND \
@@ -68,6 +70,7 @@ case $TEST_FILE in
 		SHELL_PLUGIN=$MODDIR/ivi-shell.so
 
 		set -x
+		WESTON_DATA_DIR=$abs_top_srcdir/data \
 		WESTON_BUILD_DIR=$abs_builddir \
 		WESTON_TEST_REFERENCE_PATH=$abs_top_srcdir/tests/reference \
 		WESTON_TEST_CLIENT_PATH=$abs_builddir/$TEST_FILE \
@@ -82,6 +85,7 @@ case $TEST_FILE in
 		;;
 	*)
 		set -x
+		WESTON_DATA_DIR=$abs_top_srcdir/data \
 		WESTON_BUILD_DIR=$abs_builddir \
 		WESTON_TEST_REFERENCE_PATH=$abs_top_srcdir/tests/reference \
 		WESTON_TEST_CLIENT_PATH=$abs_builddir/$TEST_FILE \