Just check for the presents of $sysfsdir/class/infiniband and check

that it's a directory.  That's good enough to know that the
OpenFabrics kernel drivers have been loaded.  If you have no RDMA
devices and don't want to see the OMPI warning about not finding any
devices, then don't start the OpenFabrics kernel drivers.

This commit was SVN r18540.

ompi/mca/btl/openib/btl_openib_component.c

@@ -29,7 +29,8 @@
 #include <errno.h>
 #include <string.h>   /* for strerror()*/
 #include <unistd.h>
-#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include "ompi/constants.h"
 #include "opal/event/event.h"
@@ -165,35 +166,23 @@ static int btl_openib_component_close(void)
 
 static bool check_basics(void)
 {
+    int rc;
     char *file;
-    DIR *dir;
-    struct dirent  *entry;
+    struct stat s;
 
-    /* Check to see if $sysfsdir/class/infiniband exists */
+    /* Check to see if $sysfsdir/class/infiniband/ exists */
     asprintf(&file, "%s/class/infiniband", ibv_get_sysfs_path());
     if (NULL == file) {
         return false;
     }
-    dir = opendir(file);
+    rc = stat(file, &s);
     free(file);
-    if (NULL == dir) {
+    if (0 != rc || !S_ISDIR(s.st_mode)) {
         return false;
     }
 
-    /* Now check to see if it is non-empty */
-    while (1) {
-        if (NULL == (entry = readdir(dir))) {
-            closedir(dir);
-            return false;
-        } else if (0 != strcmp(entry->d_name, ".") && 
-                   0 != strcmp(entry->d_name, "..")) {
-            /* The directory is not empty -- happy */
-            closedir(dir);
-            return true;
-        }
-    }
-
-    /* Never get here */
+    /* It exists and is a directory -- good enough */
+    return true;
 }
 
 static void inline pack8(char **dest, uint8_t value)