t1300: --unset-all can leave an empty section behind (bug)

We already have a test demonstrating that removing the last entry from a
config section fails to remove the section header of the now-empty
section.

The same can happen, of course, if we remove the last entries in one fell
swoop. This is *also* a bug, and should be fixed at the same time.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

t/t1300-config.sh

@@ -1472,6 +1472,17 @@ test_expect_failure '--unset last key removes section (except if commented)' '
 	test_line_count = 3 .git/config
 '
 
+test_expect_failure '--unset-all removes section if empty & uncommented' '
+	cat >.git/config <<-\EOF &&
+	[section]
+	key = value1
+	key = value2
+	EOF
+
+	git config --unset-all section.key &&
+	test_line_count = 0 .git/config
+'
+
 test_expect_failure 'adding a key into an empty section reuses header' '
 	cat >.git/config <<-\EOF &&
 	[section]