libfabric: use correct C99 notation for var-length array

Nathan pointed out the correct C99 way to notate a variable-length
array in a struct.  This change has now been accepted upstream in
libfabric.

opal/mca/common/libfabric/libfabric/include/rdma/fi_eq.h

@@ -139,13 +139,7 @@ struct fi_eq_cm_entry {
 	/* user must call fi_freeinfo to release info */
 	struct fi_info		*info;
 	/* connection data placed here, up to space provided */
-    /* Open MPI added these pragmas to stem a flood of warnings.  This
-       needs to be addressed upstream */
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpedantic"
-	uint8_t			data[0];
-    /* Open MPI added these pragmas to stem a flood of warnings.  This
-       needs to be addressed upstream */
+	uint8_t			data[];
 #pragma GCC diagnostic pop
 };