Various fixes to pre-commit hook

Fix incorrect test in sh. Bash implements the new test with [[ that
accepts the double equal, however, this is not a bash script. On Debian
and derivates, this will be run by dash.

Make the script portable by not using GNU extensions of xargs.

Call `validate-all-*.sh` scripts whenever possible.

Have bashate look for /usr/bin/env style shebang as well.

Remove useless validate-json.sh file.

Change-Id: Id2d697f2e9ddaa66e25f71f410200528c1e0cf6b

tools/pre-commit-hook

@@ -5,7 +5,7 @@ RES=0
 
 cd $TOPLEVEL
 
-if [ "$1" == "--install" ]; then
+if [ "$1" = "--install" ]; then
     ln -sf ../../tools/pre-commit-hook .git/hooks/pre-commit
     exit
 fi
@@ -26,26 +26,19 @@ find . -type f
 
 echo "=== bashate checks ==="
 
-find . -type f -print0 |
-    xargs -0 --no-run-if-empty egrep -lZ '^#!/bin/(ba)?sh' |
-    xargs -0 bashate || RES=1
+files=$(egrep -rlI '^#!/(bin/|usr/bin/env )(ba)?sh' .)
+[ "$files" ] && (bashate $files || RES=1)
 
 echo "=== yaml checks ==="
 
-find . -name '*.yaml' -print0 |
-    xargs -0 --no-run-if-empty ${TOPLEVEL}/tools/validate-yaml.py \
-        || RES = 1
+${TOPLEVEL}/tools/validate-all-yaml.sh || RES=1
 
 echo "=== json checks ==="
 
-find . -name '*.json' -print0 |
-    xargs -0 --no-run-if-empty ${TOPLEVEL}/tools/validate-json.py \
-        || RES=1
+${TOPLEVEL}/tools/validate-all-json.sh || RES=1
 
 echo "=== maintainer checks ==="
 
-find . -name Dockerfile -print0 |
-    xargs -0 --no-run-if-empty ${TOPLEVEL}/tools/validate-maintainer \
-        || RES=1
+${TOPLEVEL}/tools/validate-all-maintainer.sh || RES=1
 
 exit $RES

tools/validate-json.sh

-#!/bin/sh
-
-true