Fix if option for dev provision

Author: badrogger

datafiles/install.sh

@@ -9,7 +9,7 @@ cd $SKALE_DIR
 
 rm -rf $SKALE_NODE_DIR
 
-if [[ -z $"{SKALE_NODE_SOURCE}" ]]; then
+if [[ -z $SKALE_NODE_SOURCE ]]; then
     sudo git clone -b $GIT_BRANCH https://$GITHUB_TOKEN\@github.com/skalenetwork/skale-node.git .skale-node
 else
     rsync -r $SKALE_NODE_SOURCE/* .skale-node