[PATCH 1 of 2] test-fileset: remove bashism, use test instead of '[[ ]]'

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1434462425 -32400
#      Tue Jun 16 22:47:05 2015 +0900
# Node ID 058a621cadbfcfbd53fb40d0b6b65074b8919b37
# Parent  6ac2b6d407829c566a52d81183ccfa9a2166fe64
test-fileset: remove bashism, use test instead of '[[ ]]'

Debian dash complains about it.

  $TESTTMP.sh: 213: $TESTTMP.sh: [[: not found

diff --git a/tests/test-fileset.t b/tests/test-fileset.t
--- a/tests/test-fileset.t
+++ b/tests/test-fileset.t
@@ -226,7 +226,7 @@ saverev property is enough to alter the 
   b
   $ oldnode=`hg log -r tip -T "{node}\n"`
   $ newnode=`hg log -R ../converted -r tip -T "{node}\n"`
-  $ [[ "$oldnode" != "$newnode" ]] || echo "nothing changed"
+  $ [ "$oldnode" != "$newnode" ] || echo "nothing changed"
 
 Test with a revision