t3600: fix &&-chain breakage for setup commands

As with the earlier patch to fix "trivial" &&-chain
breakage, these missing "&&" operators are not a serious
problem (e.g., we do not expect "echo" to fail).

Ironically, however, inserting them shows that some of the
commands _do_ fail. Specifically, some of the tests start by
making sure we are at a commit with the string "content" in
the file "foo". However, running "git commit" may fail
because the previous test left us in that state already, and
there is nothing to commit.

We could remove these commands entirely, but they serve to
document the test's assumptions, as well as make it robust
when an earlier test has failed. We could use test_might_fail
to handle all cases, but that would miss an unrelated
failure to make the commit. Instead, we can just pass the
--allow-empty flag to git-commit, which means that it will
not complain if our setup is a noop.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

t/t3600-rm.sh

@@ -38,37 +38,37 @@ test_expect_success \
 
 test_expect_success \
     'Test that git rm --cached foo succeeds if the index matches the file' \
-    'echo content > foo
-     git add foo
+    'echo content >foo &&
+     git add foo &&
      git rm --cached foo'
 
 test_expect_success \
     'Test that git rm --cached foo succeeds if the index matches the file' \
-    'echo content > foo
-     git add foo
-     git commit -m foo
-     echo "other content" > foo
+    'echo content >foo &&
+     git add foo &&
+     git commit -m foo &&
+     echo "other content" >foo &&
      git rm --cached foo'
 
 test_expect_success \
     'Test that git rm --cached foo fails if the index matches neither the file nor HEAD' '
-     echo content > foo
-     git add foo
-     git commit -m foo
-     echo "other content" > foo
-     git add foo
-     echo "yet another content" > foo
+     echo content >foo &&
+     git add foo &&
+     git commit -m foo --allow-empty &&
+     echo "other content" >foo &&
+     git add foo &&
+     echo "yet another content" >foo &&
      test_must_fail git rm --cached foo
 '
 
 test_expect_success \
     'Test that git rm --cached -f foo works in case where --cached only did not' \
-    'echo content > foo
-     git add foo
-     git commit -m foo
-     echo "other content" > foo
-     git add foo
-     echo "yet another content" > foo
+    'echo content >foo &&
+     git add foo &&
+     git commit -m foo --allow-empty &&
+     echo "other content" >foo &&
+     git add foo &&
+     echo "yet another content" >foo &&
      git rm --cached -f foo'
 
 test_expect_success \