btl openib: only initialize CPCs if there are devices to use

Defer initializing the CPCs until we know that we have devices/ports
to use.  This both prevents some useless work at startup when there
are no devices/ports to use, and also prevents librdmacm complaining
that there are no verbs-capable RDMA devices available (e.g., if a
Cisco usNIC device is present, but does not present a verbs RDMA
interface).

opal/mca/btl/openib/btl_openib_component.c

@@ -2532,11 +2532,6 @@ btl_openib_component_init(int *num_btl_modules,
         goto no_btls;
     }
 
-    /* Init CPC components */
-    if (OPAL_SUCCESS != (ret = opal_btl_openib_connect_base_init())) {
-        goto no_btls;
-    }
-
     /* If we are using ptmalloc2 and there are no posix threads
        available, this will cause memory corruption.  Refuse to run.
        Right now, ptmalloc2 is the only memory manager that we have on
@@ -2792,6 +2787,12 @@ btl_openib_component_init(int *num_btl_modules,
         goto no_btls;
     }
 
+    /* Now that we know we have devices and ports that we want to use,
+       init CPC components */
+    if (OPAL_SUCCESS != (ret = opal_btl_openib_connect_base_init())) {
+        goto no_btls;
+    }
+
     /* Setup the BSRQ QP's based on the final value of
        mca_btl_openib_component.receive_queues. */
     if (OPAL_SUCCESS != setup_qps()) {