checklink: use an explicit prefix for the temporary file

mercurial/util.py

@@ -682,7 +682,7 b' def checklink(path):'
     """check whether the given path is on a symlink-capable filesystem"""
     # mktemp is not racy because symlink creation will fail if the
     # file already exists
-    name = tempfile.mktemp(dir=path)
+    name = tempfile.mktemp(dir=path, prefix='hg-checklink-')
     try:
         os.symlink(".", name)
         os.unlink(name)