tests: teach f not to report directory size

It's not meaningful or portable

tests/f

@@ -61,7 +61,7 b' def visit(opts, filenames, outfile):'
             facts.append('type unknown')
         if not isstdin:
             stat = os.lstat(f)
-            if opts.size:
+            if opts.size and not isdir:
                 facts.append('size=%s' % stat.st_size)
             if opts.mode:
                 facts.append('mode=%o' % (stat.st_mode & 0777))

tests/test-tools.t

@@ -65,7 +65,7 b' Tests of the file helper tool'
 #if unix-permissions symlink
   $ ln -s yadda l
   $ f . --recurse -MStmsB4
-  .: directory with 4 files, size=*, mode=755 (glob)
+  .: directory with 4 files, mode=755
   ./bar: file, size=21, mode=755, md5=3b03, sha1=612c
   ./baz: file, size=21, mode=755, md5=3b03, sha1=612c
   ./foo: file, size=4, mode=644, md5=d3b0, sha1=f1d2