Use downstream bootstrap-salt.sh

the upstream version recently dropped support for Ubuntu 16.04 since
it is EOL.

Related-Issue: PRODX-3456
Change-Id: I12bc558d5c1aea684c4b3dece765a5002492d705
(cherry picked from commit d67695267a204c02ca4c267620c952ab685f484e)
diff --git a/bootstrap.sh b/bootstrap.sh
index 4ac7a1e..6f3a0db 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -88,7 +88,7 @@
 
 # saltstack
 BOOTSTRAP_SALTSTACK=${BOOTSTRAP_SALTSTACK:-True}
-BOOTSTRAP_SALTSTACK_COM=${BOOTSTRAP_SALTSTACK_COM:-"https://bootstrap.saltstack.com"}
+BOOTSTRAP_SALTSTACK_COM=${BOOTSTRAP_SALTSTACK_COM:-"https://gerrit.mcp.mirantis.com/projects/salt-formulas%2Fsalt-formulas-scripts/branches/release%2F2019.2.0/files/bootstrap-salt.sh/content"}
 BOOTSTRAP_SALTSTACK_VERSION=${BOOTSTRAP_SALTSTACK_VERSION:- stable 2017.7 }
 BOOTSTRAP_SALTSTACK_VERSION=${BOOTSTRAP_SALTSTACK_VERSION//latest*/stable}
 # TODO add 'r' option by default
@@ -434,11 +434,11 @@
     case $PLATFORM_FAMILY in
       debian)
           $SUDO apt-get install -y git
-          curl -L ${BOOTSTRAP_SALTSTACK_COM} | $SUDO sh -s -- -M ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
+          curl -L ${BOOTSTRAP_SALTSTACK_COM} | base64 -d | $SUDO sh -s -- -M ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
         ;;
       rhel)
           yum install -y git
-          curl -L ${BOOTSTRAP_SALTSTACK_COM} | $SUDO sh -s -- -M ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
+          curl -L ${BOOTSTRAP_SALTSTACK_COM} | base64 -d | $SUDO sh -s -- -M ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
         ;;
     esac
 
@@ -490,10 +490,10 @@
 
     case $PLATFORM_FAMILY in
       debian)
-          curl -L ${BOOTSTRAP_SALTSTACK_COM} | $SUDO sh -s -- ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
+          curl -L ${BOOTSTRAP_SALTSTACK_COM} | base64 -d | $SUDO sh -s -- ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
       ;;
       rhel)
-          curl -L ${BOOTSTRAP_SALTSTACK_COM} | $SUDO sh -s -- ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
+          curl -L ${BOOTSTRAP_SALTSTACK_COM} | base64 -d | $SUDO sh -s -- ${BOOTSTRAP_SALTSTACK_OPTS} &>/dev/null || true
       ;;
     esac