Don't use "Head:" header for commit under cursor

This is the first line of the file so it's an annoyingly aggressive
default.

autoload/fugitive.vim

@@ -5824,7 +5824,7 @@ endfunction
 
 " Section: Go to file
 
-let s:ref_header = '\%(Head\|Merge\|Rebase\|Upstream\|Pull\|Push\)'
+let s:ref_header = '\%(Merge\|Rebase\|Upstream\|Pull\|Push\)'
 
 nnoremap <SID>: :<C-U><C-R>=v:count ? v:count : ''<CR>
 function! fugitive#MapCfile(...) abort
@@ -6040,7 +6040,7 @@ function! s:StatusCfile(...) abort
     return [lead . info.relative[0]]
   elseif len(info.commit)
     return [info.commit]
-  elseif line =~# '^' . s:ref_header . ': '
+  elseif line =~# '^' . s:ref_header . ': \|^Head: '
     return [matchstr(line, ' \zs.*')]
   else
     return ['']