Changed recipe_modules base paths to be abstract entities in their own right.

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

 [
   {
     "cmd": [
       "touch",
       "[TMP_BASE]/zip-example_tmp_1/a"
     ],
     "name": "touch a"
   },
   {
     "cmd": [
@@ skipping 28 matching lines @@
     "cmd": [
       "touch",
       "[TMP_BASE]/zip-example_tmp_1/sub/dir/c"
     ],
     "name": "touch c"
   },
   {
     "cmd": [
       "python",
       "-u",
-      "[BUILD]/scripts/slave/recipe_modules/zip/resources/zip.py"
+      "RECIPE_MODULE[zip]/resources/zip.py"
     ],
     "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",
-      "[BUILD]/scripts/slave/recipe_modules/zip/resources/zip.py"
+      "RECIPE_MODULE[zip]/resources/zip.py"
     ],
     "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"
     ],
     "name": "report"
   },
   {
     "cmd": [
       "python",
       "-u",
-      "[BUILD]/scripts/slave/recipe_modules/zip/resources/unzip.py"
+      "RECIPE_MODULE[zip]/resources/unzip.py"
     ],
     "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"
@@ skipping 10 matching lines @@
       "@@@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@@@"
     ]
   }
 ]