[pitivi] autogen: simplify check

[Thibault Saunier <tsaunier src gnome org>]

commit f3c2fa890767bfd67e254ca122ab517f560b8c50
Author: Thibault Saunier <tsaunier gnome org>
Date:   Wed Apr 20 12:04:28 2016 -0300

    autogen: simplify check

 autogen.sh |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index d6f73a2..7b1f155 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -47,12 +47,11 @@ echo
 # install pre-commit hook for doing clean commits
 rm -f .git/hooks/pre-commit
 ln -s ../../pre-commit.hook .git/hooks/pre-commit
-which pre-commit > /dev/null
-PRE_COMMIT=$?
 echo ""
-if (($PRE_COMMIT != 0)); then
+which pre-commit > /dev/null
+if [ $? -eq 0  ]; then
+  pre-commit install
+else
   echo "Please install pre-commit from http://pre-commit.com/ before proposing patches"
   echo ""
-else
-  pre-commit install
 fi