Recipes: make cwd default to slave_build

scripts/slave/recipe_modules/zip/example.expected/mac.json

 [
   {
     "cmd": [
       "touch",
       "[TMP_BASE]/zip-example_tmp_1/a"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "touch a"
   },
   {
     "cmd": [
       "touch",
       "[TMP_BASE]/zip-example_tmp_1/b"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "touch b"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[TMP_BASE]/zip-example_tmp_1/sub/dir",
       "511"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "makedirs mkdirs",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@@@@",
       "@@@STEP_LOG_LINE@python.inline@import sys, os@@@",
       "@@@STEP_LOG_LINE@python.inline@path = sys.argv[1]@@@",
       "@@@STEP_LOG_LINE@python.inline@mode = int(sys.argv[2])@@@",
       "@@@STEP_LOG_LINE@python.inline@if not os.path.isdir(path):@@@",
       "@@@STEP_LOG_LINE@python.inline@  if os.path.exists(path):@@@",
       "@@@STEP_LOG_LINE@python.inline@    print \"%s exists but is not a dir\" % path@@@",
       "@@@STEP_LOG_LINE@python.inline@    sys.exit(1)@@@",
       "@@@STEP_LOG_LINE@python.inline@  os.makedirs(path, mode)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   },
   {
     "cmd": [
       "touch",
       "[TMP_BASE]/zip-example_tmp_1/sub/dir/c"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "touch c"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[zip]/resources/zip.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "zipping",
     "stdin": "{\"entries\": [{\"path\": \"[TMP_BASE]/zip-example_tmp_1\", \"type\": \"dir\"}], \"output\": \"[TMP_BASE]/zip-example_tmp_1/output.zip\", \"root\": \"[TMP_BASE]/zip-example_tmp_1\", \"use_python_zip\": false}"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[zip]/resources/zip.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "zipping more",
     "stdin": "{\"entries\": [{\"path\": \"[TMP_BASE]/zip-example_tmp_1/a\", \"type\": \"file\"}, {\"path\": \"[TMP_BASE]/zip-example_tmp_1/b\", \"type\": \"file\"}, {\"path\": \"[TMP_BASE]/zip-example_tmp_1/sub\", \"type\": \"dir\"}], \"output\": \"[TMP_BASE]/zip-example_tmp_1/more.zip\", \"root\": \"[TMP_BASE]/zip-example_tmp_1\", \"use_python_zip\": false}"
   },
   {
     "cmd": [
       "echo",
       "[TMP_BASE]/zip-example_tmp_1/more.zip"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "report"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[zip]/resources/unzip.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "unzipping",
     "stdin": "{\"output\": \"[TMP_BASE]/zip-example_tmp_1/output\", \"use_python_zip\": false, \"zip_file\": \"[TMP_BASE]/zip-example_tmp_1/output.zip\"}"
   },
   {
     "cmd": [
       "find"
     ],
     "cwd": "[TMP_BASE]/zip-example_tmp_1/output",
     "name": "listing"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport os, sys\nfrom common import chromium_utils\n\nif os.path.exists(sys.argv[1]):\n  chromium_utils.RemoveDirectory(sys.argv[1])\n",
       "[TMP_BASE]/zip-example_tmp_1"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "rmtree cleanup",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@@@@",
       "@@@STEP_LOG_LINE@python.inline@import os, sys@@@",
       "@@@STEP_LOG_LINE@python.inline@from common import chromium_utils@@@",
       "@@@STEP_LOG_LINE@python.inline@@@@",
       "@@@STEP_LOG_LINE@python.inline@if os.path.exists(sys.argv[1]):@@@",
       "@@@STEP_LOG_LINE@python.inline@  chromium_utils.RemoveDirectory(sys.argv[1])@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   }
 ]