Fixed an issue of indicator of Vi mode

Fixed an issue that the indicator of Vi mode won't appear correctly at
first.

powerlevel9k.zsh-theme

@@ -1192,12 +1192,12 @@ set_default POWERLEVEL9K_VI_INSERT_MODE_STRING "INSERT"
 set_default POWERLEVEL9K_VI_COMMAND_MODE_STRING "NORMAL"
 prompt_vi_mode() {
   case ${KEYMAP} in
-    main|viins)
-      "$1_prompt_segment" "$0_INSERT" "$2" "$DEFAULT_COLOR" "blue" "$POWERLEVEL9K_VI_INSERT_MODE_STRING"
-    ;;
     vicmd)
       "$1_prompt_segment" "$0_NORMAL" "$2" "$DEFAULT_COLOR" "default" "$POWERLEVEL9K_VI_COMMAND_MODE_STRING"
     ;;
+    main|viins|*)
+      "$1_prompt_segment" "$0_INSERT" "$2" "$DEFAULT_COLOR" "blue" "$POWERLEVEL9K_VI_INSERT_MODE_STRING"
+    ;;
   esac
 }