t3[5-9]*: adjust the references to the default branch name "main"

This trick was performed via

	$ (cd t &&
	   sed -i -e 's/master/main/g' -e 's/MASTER/MAIN/g' \
		-e 's/Master/Main/g' -- t3[5-9]*.sh)

This allows us to define `GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main`
for those tests.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t3509-cherry-pick-merge-df.sh b/t/t3509-cherry-pick-merge-df.sh
index 83cab7b..f415924 100755
--- a/t/t3509-cherry-pick-merge-df.sh
+++ b/t/t3509-cherry-pick-merge-df.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 test_description='Test cherry-pick with directory/file conflicts'
-GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
@@ -31,7 +31,7 @@
 
 test_expect_success 'Cherry-pick succeeds with rename across D/F conflicts' '
 	git reset --hard &&
-	git checkout master^0 &&
+	git checkout main^0 &&
 	git cherry-pick branch
 '