test-lfs: fix expected output

This is not covered by the CI and was broken.

Differential Revision: https://phab.mercurial-scm.org/D10397

tests/test-lfs-test-server.t

@@ -115,7 +115,7 b' store.'
   Status: 200 (git-server !)
   Status: 201 (hg-server !)
   Content-Length: 0
-  Content-Type: text/plain; charset=utf-8
+  Content-Type: text/plain; charset=utf-8 (hg-server !)
   Date: $HTTP_DATE$
   Server: testing stub value (hg-server !)
   lfs: processed: 31cf46fbc4ecd458a0943c5b4881f1f5a6dd36c53d6167d5b69ac45149b38e5b
@@ -279,7 +279,7 b' actions property completely.'
   Status: 200 (git-server !)
   Status: 201 (hg-server !)
   Content-Length: 0
-  Content-Type: text/plain; charset=utf-8
+  Content-Type: text/plain; charset=utf-8 (hg-server !)
   Date: $HTTP_DATE$
   Server: testing stub value (hg-server !)
   lfs: processed: 37a65ab78d5ecda767e8622c248b5dbff1e68b1678ab0e730d5eb8601ec8ad19
@@ -287,7 +287,7 b' actions property completely.'
   Status: 200 (git-server !)
   Status: 201 (hg-server !)
   Content-Length: 0
-  Content-Type: text/plain; charset=utf-8
+  Content-Type: text/plain; charset=utf-8 (hg-server !)
   Date: $HTTP_DATE$
   Server: testing stub value (hg-server !)
   lfs: processed: d11e1a642b60813aee592094109b406089b8dff4cb157157f753418ec7857998