[PATCH] readahead: do not call -@ on non-String

[Eric Wong]

There may not be an `infile' element in the `current' response.

Fixes: bf9787ac517fe19a ("deduplicate and freeze pathnames + metadata")
---
 bin/dtas-readahead | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/bin/dtas-readahead b/bin/dtas-readahead
index 6da5f88..f2ab514 100755
--- a/bin/dtas-readahead
+++ b/bin/dtas-readahead
@@ -145,8 +145,9 @@ def do_open(path)
   cur = DTAS.yaml_load(c.req('current'))
   while @todo_ra > 0 && fp.nil?
     if current = cur['current']
-      track = -current['infile']
+      track = current['infile']
       break unless track.kind_of?(String)
+      track = -track
       fp = work[track] ||= do_open(track)
       cur_pid = current['pid']
       if fp