Fail on error and print diffs generated in CCP TINC tests

Fail on error instead of continuing on. If the test fails, we will search for
diff files in the TINC directory and print them all out. This will allow us to
see the diff file contents from the Concourse job UI. The trap function is
copied from the run_tinc_test.sh native Concourse TINC test script.

concourse/scripts/run_tinc_test.sh

 #!/bin/bash
+set -eox pipefail
 
-TINC_TARGET="$@"
-TINC_DIR=/home/gpadmin/gpdb_src/src/test/tinc
+TINCTARGET="$@"
+TINCDIR=/home/gpadmin/gpdb_src/src/test/tinc
 
 cat > ~/gpdb-env.sh << EOF
   source /usr/local/greenplum-db-devel/greenplum_path.sh
@@ -10,7 +11,7 @@ cat > ~/gpdb-env.sh << EOF
   export PGDATABASE=gptest
 
   alias mdd='cd \$MASTER_DATA_DIRECTORY'
-  alias tinc='cd ${TINC_DIR}'
+  alias tinc='cd ${TINCDIR}'
 EOF
 source ~/gpdb-env.sh
 
@@ -22,6 +23,16 @@ gpconfig --skipvalidation -c fsync -v off
 gpstop -u
 gpconfig -s fsync
 
-cd ${TINC_DIR}
+trap look4diffs ERR
+function look4diffs() {
+    find ${TINCDIR} -name *.diff -exec cat {} \; >> ${TINCDIR}/regression.diffs
+    echo "=================================================================="
+    echo "The differences that may have caused some tests to fail can be viewed in the file ${TINCDIR}/regression.diffs."
+    echo "=================================================================="
+    cat ${TINCDIR}/regression.diffs
+    exit 1
+}
+
+cd ${TINCDIR}
 source tinc_env.sh
-make ${TINC_TARGET}
+make ${TINCTARGET}