{src,include}/sm_io_err*: add new "Could not register SM" error

include/sm_io_err.h

@@ -29,6 +29,7 @@ enum _smio_err_e {
     SMIO_ERR_INTERRUPTED_POLLER,    /* SMIO Poller interrupted. zeroMQ context was
                                        terminated or received interrupt signal */
     SMIO_ERR_INV_SOCKET,            /* Invalid socket reference */
+    SMIO_ERR_REGISTER_SM,           /* Could not register SMIO */
     SMIO_ERR_END                    /* End of enum marker */
 };
 

src/sm_io/sm_io_err.c

@@ -24,7 +24,8 @@ static const char *smio_err [SMIO_ERR_END] =
     [SMIO_ERR_BAD_MSG]              = "Malformed message received",
     [SMIO_ERR_INTERRUPTED_POLLER]   = "Poller interrupted. zeroMQ context was "
         "terminated or received interrupt signal",
-    [SMIO_ERR_INV_SOCKET]           = "Invalid socket reference"
+    [SMIO_ERR_INV_SOCKET]           = "Invalid socket reference",
+    [SMIO_ERR_REGISTER_SM]          = "Could not register SMIO"
 };
 
 /* Convert enumeration type to string */