vm_shell: validate selected CID

Avoid mistype

Bug: N/A
Test: manual
Change-Id: I26402bb6af786683cd2294758749796b8a67afd0
diff --git a/vm/vm_shell.sh b/vm/vm_shell.sh
index ec9243b..8217901 100755
--- a/vm/vm_shell.sh
+++ b/vm/vm_shell.sh
@@ -40,12 +40,7 @@
     exit 1
 fi
 
-if [ -n "${selected_cid}" ]; then
-    if [[ ! " ${available_cids[*]} " =~ " ${selected_cid} " ]]; then
-        echo VM of CID $selected_cid does not exist. Available CIDs: ${available_cids}
-        exit 1
-    fi
-else
+if [ ! -n "${selected_cid}" ]; then
     PS3="Select CID of VM to adb-shell into: "
     select cid in ${available_cids}
     do
@@ -54,4 +49,9 @@
     done
 fi
 
+if [[ ! " ${available_cids[*]} " =~ " ${selected_cid} " ]]; then
+    echo VM of CID $selected_cid does not exist. Available CIDs: ${available_cids}
+    exit 1
+fi
+
 connect_vm ${selected_cid}