jenkins.sh: cosmetic: export instead of inlining PATH env

Change-Id: I24a383140f2f84e90ab743691bcbf041de7b034d
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 772b85d..e315b4f 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -14,6 +14,8 @@
 
 cd ../../
 autoreconf --install --force
-PKG_CONFIG_PATH=$PWD/deps/install/lib/pkgconfig:$PKG_CONFIG_PATH ./configure
-PKG_CONFIG_PATH=$PWD/deps/install/lib/pkgconfig:$PKG_CONFIG_PATH $MAKE $PARALLEL_MAKE
-PKG_CONFIG_PATH=$PWD/deps/install/lib/pkgconfig:$PKG_CONFIG_PATH LD_LIBRARY_PATH=$PWD/deps/install/lib $MAKE distcheck
+export PKG_CONFIG_PATH=$PWD/deps/install/lib/pkgconfig:$PKG_CONFIG_PATH
+export LD_LIBRARY_PATH=$PWD/deps/install/lib
+./configure
+$MAKE $PARALLEL_MAKE
+$MAKE distcheck