patch 7.4.1552
Problem:    ":colorscheme" does not use 'packpath'.
Solution:   Also use in "start" and "opt" directories in 'packpath'.
diff --git a/src/testdir/test_packadd.vim b/src/testdir/test_packadd.vim
index 008bb93..3ca8375 100644
--- a/src/testdir/test_packadd.vim
+++ b/src/testdir/test_packadd.vim
@@ -114,3 +114,23 @@
   let tags2 = readfile(docdir2 . '/tags') 
   call assert_true(tags2[0] =~ 'look-away')
 endfunc
+
+func Test_colorscheme()
+  let colordirrun = &packpath . '/runtime/colors'
+  let colordirstart = &packpath . '/pack/mine/start/foo/colors'
+  let colordiropt = &packpath . '/pack/mine/opt/bar/colors'
+  call mkdir(colordirrun, 'p')
+  call mkdir(colordirstart, 'p')
+  call mkdir(colordiropt, 'p')
+  call writefile(['let g:found_one = 1'], colordirrun . '/one.vim')
+  call writefile(['let g:found_two = 1'], colordirstart . '/two.vim')
+  call writefile(['let g:found_three = 1'], colordiropt . '/three.vim')
+  exe 'set rtp=' . &packpath . '/runtime'
+
+  colorscheme one
+  call assert_equal(1, g:found_one)
+  colorscheme two
+  call assert_equal(1, g:found_two)
+  colorscheme three
+  call assert_equal(1, g:found_three)
+endfunc