Update vmcreate.sh

vmcreate.sh

@@ -227,6 +227,10 @@ if [ $pubkey ]; then
 else
     read -p "Public key not specified. Use default? Enter to continue or Ctrl+C to abort"
 fi
+if [[ (head -c 7 "$pubkey") -ne "ssh-rsa" ]]; then
+    echo "$pubkey is not a valid public key. Make sure you specified PUBLIC key."
+    exit 6
+fi
 
 # Проверяем, что нет ВМ в списке и нет сниппетов
 for line in $(cat hosts.tmp)