fix: make devnet work consistently on macOS

Author: jpraynaud

mithril-test-lab/mithril-devnet/devnet-mkfiles.sh

@@ -3,7 +3,7 @@
 set -e
 
 # Debug mode
-if [ -v DEBUG ]; then
+if [[ -n $DEBUG ]]; then
     set -x
 fi
 

mithril-test-lab/mithril-devnet/mkfiles/mkfiles-cardano.sh

@@ -25,7 +25,7 @@ INIT_SUPPLY=12000000
 TOTAL_SUPPLY=2000000000000
 DELEGATED_SUPPLY=240000000002
 SECURITY_PARAM=2
-START_GENESIS_DELAY=1
+START_GENESIS_DELAY=5
 
 START_TIME="$(${DATE} -d "now + ${START_GENESIS_DELAY} seconds" +%s)"