Avoid using `echo -n` anywhere

`echo -n` is non-portable. The POSIX specification says:

    Conforming applications that wish to do prompting without <newline>
    characters or that could possibly be expecting to echo a -n, should
    use the printf utility derived from the Ninth Edition system.

Since all of the affected shell scripts use a POSIX shell shebang,
replace `echo -n` invocations with printf.

Signed-off-by: Lukas Fleischer <git@cryptocrack.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/subtree/git-subtree.sh

@@ -311,7 +311,7 @@ copy_commit()
 			GIT_COMMITTER_NAME \
 			GIT_COMMITTER_EMAIL \
 			GIT_COMMITTER_DATE
-		(echo -n "$annotate"; cat ) |
+		(printf "%s" "$annotate"; cat ) |
 		git commit-tree "$2" $3  # reads the rest of stdin
 	) || die "Can't copy commit $1"
 }

contrib/subtree/t/t7900-subtree.sh

@@ -182,9 +182,9 @@ test_expect_success 'merge new subproj history into subdir' '
 test_expect_success 'Check that prefix argument is required for split' '
         echo "You must provide the --prefix option." > expected &&
         test_must_fail git subtree split > actual 2>&1 &&
-        test_debug "echo -n expected: " &&
+	test_debug "printf '"'"'expected: '"'"'" &&
         test_debug "cat expected" &&
-        test_debug "echo -n actual: " &&
+	test_debug "printf '"'"'actual: '"'"'" &&
         test_debug "cat actual" &&
         test_cmp expected actual &&
         rm -f expected actual
@@ -193,9 +193,9 @@ test_expect_success 'Check that prefix argument is required for split' '
 test_expect_success 'Check that the <prefix> exists for a split' '
         echo "'"'"'non-existent-directory'"'"'" does not exist\; use "'"'"'git subtree add'"'"'" > expected &&
         test_must_fail git subtree split --prefix=non-existent-directory > actual 2>&1 &&
-        test_debug "echo -n expected: " &&
+	test_debug "printf '"'"'expected: '"'"'" &&
         test_debug "cat expected" &&
-        test_debug "echo -n actual: " &&
+	test_debug "printf '"'"'actual: '"'"'" &&
         test_debug "cat actual" &&
         test_cmp expected actual
 #        rm -f expected actual

t/perf/perf-lib.sh

@@ -160,7 +160,7 @@ test_perf () {
 		echo "$test_count" >>"$perf_results_dir"/$base.subtests
 		echo "$1" >"$perf_results_dir"/$base.$test_count.descr
 		if test -z "$verbose"; then
-			echo -n "perf $test_count - $1:"
+			printf "%s" "perf $test_count - $1:"
 		else
 			echo "perf $test_count - $1:"
 		fi
@@ -169,7 +169,7 @@ test_perf () {
 			if test_run_perf_ "$2"
 			then
 				if test -z "$verbose"; then
-					echo -n " $i"
+					printf " %s" "$i"
 				else
 					echo "* timing run $i/$GIT_PERF_REPEAT_COUNT:"
 				fi