travis_lint_format: skip deleted files

scripts/travis_lint_format.sh

diff --git a/scripts/travis_lint_format.sh b/scripts/travis_lint_format.sh
index b111cc4..730c4e5 100755
--- a/scripts/travis_lint_format.sh
+++ b/scripts/travis_lint_format.sh
@@ -12,7 +12,7 @@
 
 skipped_directories="(examples|generator|src/tests/(unittests|end2end)|third_party)"
 # Find the files modified that need formatting
-files_to_check=$(git diff --name-only $base_commit | grep -E "*.(c|cpp|mm|h)$" | grep -vE "^$skipped_directories/*")
+files_to_check=$(git diff --diff-filter=ACMR --name-only $base_commit | grep -E "*.(c|cpp|mm|h)$" | grep -vE "^$skipped_directories/*")
 if [ -z "$files_to_check" ]; then
     echo "No modified files to format."
     exit 0