Be more verbose

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

src/path.c

@@ -99,9 +99,20 @@ gt_path(int argc, char **argv)
 
     int fd = ctl_connect(GT_RUNDIR, dev);
 
-    if (fd == -1) {
-        perror("path");
-        ctl_delete(fd);
+    if (fd < 0) {
+        switch (fd) {
+        case -1:
+            perror("path");
+            break;
+        case -2:
+            gt_log("no device\n");
+            break;
+        case -3:
+            gt_log("please choose a device\n");
+            break;
+        default:
+            gt_log("couldn't connect\n");
+        }
         return 1;
     }