t4151 missing quotes

Hi there,

skipping through some failed tests I found more (smaller) problems
inside the test... when test arguments are empty they need to be
quoted (quite a lot test in this sentence).

Error is like
t4151-am-abort.sh[5]: test: argument expected

My patch:

*** t4151-am-abort.sh   Mon May  9 17:51:44 2016

--- t4151-am-abort.sh.orig      Fri Apr 29 23:37:00 2016

***************
*** 67,73 ****
  test_expect_success 'am -3 --skip removes otherfile-4' '
        git reset --hard initial &&
        test_must_fail git am -3 0003-*.patch &&
!       test 3 -eq "$(git ls-files -u | wc -l)" &&
        test 4 = "$(cat otherfile-4)" &&
        git am --skip &&
        test_cmp_rev initial HEAD &&

--- 67,73 ----
  test_expect_success 'am -3 --skip removes otherfile-4' '
        git reset --hard initial &&
        test_must_fail git am -3 0003-*.patch &&

!       test 3 -eq $(git ls-files -u | wc -l) &&
        test 4 = "$(cat otherfile-4)" &&
        git am --skip &&
        test_cmp_rev initial HEAD &&
***************
*** 78,88 ****
  test_expect_success 'am -3 --abort removes otherfile-4' '
        git reset --hard initial &&
        test_must_fail git am -3 0003-*.patch &&
!       test 3 -eq "$(git ls-files -u | wc -l)" &&
        test 4 = "$(cat otherfile-4)" &&
        git am --abort &&
        test_cmp_rev initial HEAD &&
!       test -z "$(git ls-files -u)" &&
        test_path_is_missing otherfile-4
  '

--- 78,88 ----
  test_expect_success 'am -3 --abort removes otherfile-4' '
        git reset --hard initial &&
        test_must_fail git am -3 0003-*.patch &&

!       test 3 -eq $(git ls-files -u | wc -l) &&
        test 4 = "$(cat otherfile-4)" &&
        git am --abort &&
        test_cmp_rev initial HEAD &&
!       test -z $(git ls-files -u) &&
        test_path_is_missing otherfile-4
  '

***************
*** 146,152 ****
        git reset &&
        rm -f otherfile-4 otherfile-2 file-1 file-2 &&
        test_must_fail git am -3 initial.patch 0003-*.patch &&
!       test 3 -eq "$(git ls-files -u | wc -l)" &&
        test 4 = "$(cat otherfile-4)" &&
        git am --abort &&
        test -z "$(git ls-files -u)" &&

--- 146,152 ----
        git reset &&
        rm -f otherfile-4 otherfile-2 file-1 file-2 &&
        test_must_fail git am -3 initial.patch 0003-*.patch &&

!       test 3 -eq $(git ls-files -u | wc -l) &&
        test 4 = "$(cat otherfile-4)" &&
        git am --abort &&
        test -z "$(git ls-files -u)" &&

Regards,
Armin