vcl: register workers when reattaching to vpp

Type: improvement
Signed-off-by: Maros Ondrejicka <maros.ondrejicka@pantheon.tech>
Change-Id: I82a286e2872338974c1930138c30db78103ae499
diff --git a/src/vcl/vcl_sapi.c b/src/vcl/vcl_sapi.c
index 7d677e9..3a97fa2 100644
--- a/src/vcl/vcl_sapi.c
+++ b/src/vcl/vcl_sapi.c
@@ -59,6 +59,8 @@
     }
 
   wrk->api_client_handle = mp->api_client_handle;
+  /* reattaching via `vcl_api_retry_attach` wants wrk->vpp_wrk_index to be 0 */
+  wrk->vpp_wrk_index = 0;
   segment_handle = mp->segment_handle;
   if (segment_handle == VCL_INVALID_SEGMENT_HANDLE)
     {