fix incorrect version being displayed for linux static builds

This was because "git clone -s" does not work properly in the chroot,
and hence making it impossible to evaluate "git describe --tags".

build_linux.sh

@@ -59,8 +59,8 @@ function setup_chroot() {
 
 	sudo rm -fR linux-$1/source
 	sudo chown --reference=${BASE} linux-$1
-	git clone -s ${BASE} linux-$1/source
-	git clone -s ${BASE}/qt linux-$1/source/qt
+	git clone ${BASE} linux-$1/source
+	git clone ${BASE}/qt linux-$1/source/qt
 	cd ${BUILD}/linux-$1/source
 	git submodule init
 	git submodule update --no-fetch