CI simplification/improvements for buildifier (#113)

* buildifier 0.22.0 includes files names in diffs.

* Simplify buildifier runs even more.

Since exit status are more consistently set and output is generally better,
don't bother being as fancy and just print a simple line as lead in incase
issues are found, and use the exit status to print directions on what to
do if something comes up.
diff --git a/.travis_build.sh b/.travis_build.sh
index 706a054..f160280 100755
--- a/.travis_build.sh
+++ b/.travis_build.sh
@@ -41,43 +41,30 @@
 
   # Check for format issues?
   if [[ "${FORMAT:-yes}" == "yes" ]] ; then
-    # bazelbuild/buildtools/issues/220 - diff doesn't include the file that needs updating
-    if ! find . "${FIND_ARGS[@]}" -print | xargs buildifier -d > /dev/null 2>&1 ; then
-      if [[ "${FOUND_ISSUES}" != "no" ]] ; then
-        echo ""
-      fi
-      echo "ERROR: BUILD/.bzl file formatting issue(s):"
-      echo ""
-      # bazelbuild/buildtools/issues/329 - sed out the exit status lines.
-      find . "${FIND_ARGS[@]}" -print -exec buildifier -v -d {} \; \
-          2>&1 | sed -E -e '/^exit status 1$/d'
+    echo "buildifier: validating formatting..."
+    if ! find . "${FIND_ARGS[@]}" -print | xargs buildifier -d ; then
       echo ""
       echo "Please download the latest buildifier"
       echo "   https://github.com/bazelbuild/buildtools/releases"
       echo "and run it over the changed BUILD/.bzl files."
+      echo ""
       FOUND_ISSUES="yes"
     fi
   fi
 
   # Check for lint issues?
   if [[ "${LINT:-yes}" == "yes" ]] ; then
+    echo "buildifier: running lint checks..."
     # NOTE: buildifier defaults to --mode=fix, so these lint runs also
     # reformat the files. But since this is on travis, that is fine.
     # https://github.com/bazelbuild/buildtools/issues/453
-    if ! find . "${FIND_ARGS[@]}" -print | xargs buildifier --lint=warn > /dev/null 2>&1 ; then
-      if [[ "${FOUND_ISSUES}" != "no" ]] ; then
-        echo ""
-      fi
-      echo "ERROR: BUILD/.bzl lint issue(s):"
-      echo ""
-      # buildifier now exits with error if there are issues, so use `|| true`
-      # to keep the script running.
-      find . "${FIND_ARGS[@]}" -print | xargs buildifier --lint=warn || true
+    if ! find . "${FIND_ARGS[@]}" -print | xargs buildifier --lint=warn ; then
       echo ""
       echo "Please download the latest buildifier"
       echo "   https://github.com/bazelbuild/buildtools/releases"
       echo "and run it with --lint=(warn|fix) over the changed BUILD/.bzl files"
       echo "and make the edits as needed."
+      echo ""
       FOUND_ISSUES="yes"
     fi
   fi