Fix missing shebang in failover shell scripts

src/bin/gpfts/failover/docker_master_check_back.sh

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 
 if !type gpssh >/dev/null 2>&1; then 
     echo "[FATAL]:- gpssh not exist, script Exits!"

src/bin/gpfts/failover/docker_segment_check_back.sh

@@ -1,4 +1,4 @@
-
+#!/usr/bin/env bash
 
 if !type gpssh >/dev/null 2>&1; then 
     echo "[FATAL]:- gpssh not exist, script Exits!"

src/bin/gpfts/failover/docker_standby_check_back.sh

@@ -1,4 +1,4 @@
-
+#!/usr/bin/env bash
 
 if !type gpssh >/dev/null 2>&1; then 
     echo "[FATAL]:- gpssh not exist, script Exits!"

src/bin/gpfts/failover/master_check_back.sh

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 
 if !type gpssh >/dev/null 2>&1; then 
     echo "[FATAL]:- gpssh not exist, script Exits!"

src/bin/gpfts/failover/segment_all_down.sh

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 
 if !type pg_ctl >/dev/null 2>&1; then 
     echo "[FATAL]:- pg_ctl not exist, script Exits!"

src/bin/gpfts/failover/segment_check_back.sh

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 
 if !type gprecoverseg >/dev/null 2>&1; then 
     echo "[FATAL]:- gprecoverseg not exist, script Exits!"

src/bin/gpfts/failover/standby_check_back.sh

@@ -1,4 +1,4 @@
-
+#!/usr/bin/env bash
 
 if !type gpssh >/dev/null 2>&1; then 
     echo "[FATAL]:- gpssh not exist, script Exits!"