Fix test failures and warnings of WARPED_MOTION

Properly set number of projection samples for seg skip blocks
at the encoder side to clear unit test failure when both seg feature
and warped_motion is on.
Clear 'implicit conversions' warnings

Change-Id: I29e40ffae75880dae2584dbc8772c81321f6d69e
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index eeeb91a..c1f8cc7 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -11517,6 +11517,12 @@
 #if CONFIG_MOTION_VAR
   av1_count_overlappable_neighbors(cm, xd, mi_row, mi_col);
 #endif
+#if CONFIG_WARPED_MOTION
+  if (is_motion_variation_allowed_bsize(bsize) && !has_second_ref(mbmi)) {
+    int pts[SAMPLES_ARRAY_SIZE], pts_inref[SAMPLES_ARRAY_SIZE];
+    mbmi->num_proj_ref[0] = findSamples(cm, xd, mi_row, mi_col, pts, pts_inref);
+  }
+#endif
 
   if (cm->interp_filter != BILINEAR) {
     best_filter = EIGHTTAP_REGULAR;