Update .vimrc

repaired a invalid warning form <script></script>. <script> is not support contain any html tag. We can use <code>:help syntastic</code> command to show how to disable syntax checking for a given filetype:
let g:syntastic_mode_map={ 'mode': 'active',
                     \ 'active_filetypes': [],
                     \ 'passive_filetypes': ['html'] }