ci: Give some time to the disk hotplug

Under high load, the VM might take some time to hotplug the disk after
the hotplug command has been issued. For this reason, let's put a 10s
sleep before checking for the presence of the new disk.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

tests/integration.rs

@@ -4262,6 +4262,8 @@ mod tests {
                         .contains("{\"id\":\"test0\",\"bdf\":\"0000:00:06.0\"}")
                 );
 
+                thread::sleep(std::time::Duration::new(10, 0));
+
                 // Check that if /dev/vdc exists and the block size is 16M.
                 aver_eq!(
                     tb,