[pitivi] autogen: Fix use of PRE_COMMIT variable

[Thibault Saunier <tsaunier src gnome org>]

commit c1da51f4105178c3d5a6fd96e6a693a34b62a99c
Author: Thibault Saunier <tsaunier gnome org>
Date:   Wed Apr 20 11:39:06 2016 -0300

    autogen: Fix use of PRE_COMMIT variable

 autogen.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 69742ec..d6f73a2 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -50,7 +50,7 @@ ln -s ../../pre-commit.hook .git/hooks/pre-commit
 which pre-commit > /dev/null
 PRE_COMMIT=$?
 echo ""
-if ((PRE_COMMIT != 0)); then
+if (($PRE_COMMIT != 0)); then
   echo "Please install pre-commit from http://pre-commit.com/ before proposing patches"
   echo ""
 else