travis: used own retry script, since travis_retry does not work in makefile

Makefile

@@ -6,10 +6,10 @@ KOPIA_INTEGRATION_EXE=$(CURDIR)/dist/integration/kopia.exe
 
 all: test lint vet integration-tests
 
-maybe_travis_retry=
+retry=
 
 ifneq ($(TRAVIS_OS_NAME),)
-maybe_travis_retry=travis_retry
+retry=$(CURDIR)/tools/retry.sh
 endif
 
 include tools/tools.mk
@@ -73,9 +73,9 @@ kopia-ui: goreleaser
 	$(MAKE) -C app build-electron
 
 travis-release:
-	$(maybe_travis_retry) $(MAKE) goreleaser kopia-ui
+	$(retry) $(MAKE) goreleaser kopia-ui
 	$(MAKE) lint vet test-with-coverage html-ui-tests
-	$(maybe_travis_retry) $(MAKE) integration-tests
+	$(retry) $(MAKE) integration-tests
 ifeq ($(TRAVIS_OS_NAME),linux)
 	$(MAKE) website
 	$(MAKE) stress-test

tools/retry.sh

@@ -0,0 +1,7 @@
+for attempt in 1 2 3; do
+  echo "+ $@ (attempt $attempt)"
+  if "$@"; then
+    exit 0
+  fi
+done
+exit 1