Return bundle status without using git output text

Instead checking for specific text in the output of the git commands, determine
the status of the bundle by comparing the sha of HEAD before and after the
git pull command.

autoload/vundle/installer.vim

@@ -212,8 +212,12 @@ func! s:sync(bang, bundle) abort
       let cmd = substitute(cmd, '^cd ','cd /d ','')  " add /d switch to change drives
       let cmd = '"'.cmd.'"'                          " enclose in quotes
     endif
+
+    let get_current_sha = 'cd '.shellescape(a:bundle.path()).' && git rev-parse HEAD'
+    let initial_sha = s:system(get_current_sha)[0:15]
   else
     let cmd = 'git clone '.a:bundle.uri.' '.shellescape(a:bundle.path())
+    let initial_sha = ''
   endif
 
   let out = s:system(cmd)
@@ -226,31 +230,24 @@ func! s:sync(bang, bundle) abort
     return 'error'
   end
 
-  if out =~# 'Cloning into '
+  if empty(initial_sha)
     return 'new'
-  elseif out =~# 'up-to-date'
+  endif
+
+  let updated_sha = s:system(get_current_sha)[0:15]
+
+  if initial_sha == updated_sha
     return 'todate'
   endif
 
-  call s:add_to_updated_bundles(out, a:bundle)
+  call add(g:updated_bundles, [initial_sha, updated_sha, a:bundle])
   return 'updated'
 endf
 
 func! s:system(cmd) abort
   return system(a:cmd)
 endf
 
-func! s:add_to_updated_bundles(out, bundle) abort
-  let git_pull_shas = matchlist(a:out, 'Updating \(\w\+\)..\(\w\+\)')
-
-  if (empty(git_pull_shas)) | return | endif
-
-  let initial_sha = git_pull_shas[1]
-  let updated_sha = git_pull_shas[2]
-
-  call add(g:updated_bundles, [initial_sha, updated_sha, a:bundle])
-endfunc
-
 func! s:log(str) abort
   let fmt = '%y%m%d %H:%M:%S'
   call add(g:vundle_log, '['.strftime(fmt).'] '.a:str)