Fixing index when users need to choose multiple images.

Bug:120723082

Test: 1. $acloud delete , check if any side effect.
      2. $acloud create --local-image , check the index is correct or
      not.

Change-Id: Id2cce348d0dfe9735559ec12b47b7833068f3fc9
diff --git a/internal/lib/utils.py b/internal/lib/utils.py
index 682a177..f7df259 100755
--- a/internal/lib/utils.py
+++ b/internal/lib/utils.py
@@ -822,14 +822,17 @@
     """
     print("[0] to exit.")
     start_index = 1
+    max_choice = len(answer_list)
+
     if enable_choose_all:
         start_index = 2
+        max_choice += 1
         print("[1] for all.")
     for num, item in enumerate(answer_list, start_index):
         print("[%d] %s" % (num, item))
 
     choice = -1
-    max_choice = len(answer_list) + 1
+
     while True:
         try:
             choice = raw_input("Enter your choice[0-%d]: " % max_choice)