Bug fix for issue #90 caused by pull request #84 (async refactor)

See issue 90 on GitHub:
  #90

This was caused by the async refactor:
  #84

Author: xolox

autoload/xolox/easytags.vim

@@ -3,7 +3,7 @@
 " Last Change: August 8, 2014
 " URL: http://peterodding.com/code/vim/easytags/
 
-let g:xolox#easytags#version = '3.6.4'
+let g:xolox#easytags#version = '3.6.6'
 let g:xolox#easytags#default_pattern_prefix = '\C\<'
 let g:xolox#easytags#default_pattern_suffix = '\>'
 

autoload/xolox/easytags/update.vim

@@ -1,6 +1,6 @@
 " Vim script
 " Author: Peter Odding <peter@peterodding.com>
-" Last Change: June 30, 2014
+" Last Change: August 8, 2014
 " URL: http://peterodding.com/code/vim/easytags/
 
 " This Vim auto-load script contains the parts of vim-easytags that are used
@@ -151,7 +151,12 @@ function! xolox#easytags#update#read_tagsfile(tagsfile) " {{{1
   let headers = []
   let entries = []
   let num_invalid = 0
-  for line in readfile(a:tagsfile)
+  if filereadable(a:tagsfile)
+    let lines = readfile(a:tagsfile)
+  else
+    let lines = []
+  endif
+  for line in lines
     if line =~# '^!_TAG_'
       call add(headers, line)
     else