Remove unneeded unmaps from b:undo_ftplugin

The "im" and "am" mappings are present a bit later in the file and the
"ic" and "ac" mappings are not relevant anymore.

Author: AndrewRadev

ftplugin/ruby.vim

@@ -130,7 +130,6 @@ if !exists("g:no_plugin_maps") && !exists("g:no_ruby_maps")
   let b:undo_ftplugin = b:undo_ftplugin
         \."| sil! exe 'unmap <buffer> [[' | sil! exe 'unmap <buffer> ]]' | sil! exe 'unmap <buffer> []' | sil! exe 'unmap <buffer> ]['"
         \."| sil! exe 'unmap <buffer> [m' | sil! exe 'unmap <buffer> ]m' | sil! exe 'unmap <buffer> [M' | sil! exe 'unmap <buffer> ]M'"
-        \."| sil! exe 'ounmap <buffer> im'| sil! exe 'ounmap <buffer> am'| sil! exe 'ounmap <buffer> ic'| sil! exe 'ounmap <buffer> ac'"
 
   if maparg('im','n') == ''
     onoremap <silent> <buffer> im :<C-U>call <SID>wrap_i('[m',']M')<CR>