oshmem/ucx: fixed a build issue

Co-authored with: Artem Polyakov <artemp@mellanox.com>

Signed-off-by: Tomislav Janjusic <tomislavj@mellanox.com>

oshmem/mca/sshmem/ucx/sshmem_ucx_module.c

@@ -226,6 +226,7 @@ segment_create(map_segment_t *ds_buf,
     unsigned flags;
 
 #if HAVE_UCX_DEVICE_MEM
+    int ret = OSHMEM_ERROR;
     if (hint & SHMEM_HINT_DEVICE_NIC_MEM) {
         if (size > UINT_MAX) {
             return OSHMEM_ERR_BAD_PARAM;