CrxCache: don't remove the unencrypted crx cache after import.

This functionality is being moved to chromeos-cleanup-logs which is run once a
day. We've decided to move cleanup from the import to our logs scrubber to
assist with some factory flow cases.

BUG=chromium:345335
TEST=Ran it on a device.

Change-Id: I87404606d04a28fae5fb9941a442a714b61ea782
Reviewed-on: https://chromium-review.googlesource.com/187340
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Chris Sosa <sosa@chromium.org>
Tested-by: Chris Sosa <sosa@chromium.org>

crx-import.conf

diff --git a/crx-import.conf b/crx-import.conf
index 6811fcd..76e0cce 100644
--- a/crx-import.conf
+++ b/crx-import.conf
@@ -17,6 +17,7 @@
     exit 0
   fi
 
+  # Note these paths are shared with platform/init/chromeos-cleanup-logs.
   FROM=/mnt/stateful_partition/unencrypted/import_extensions
   TO=/var/cache/external_cache
   VALIDATION=/usr/share/import_extensions/validation
@@ -45,13 +46,4 @@
   # has finished. It should be created, even if we weren't actually able to
   # import anything.
   touch "${TO}/.initialized"
-
-  # Success or failure, we remove the source files. However, if we are on
-  # removable media, we want to leave them around so they'll be there for
-  # chromeos-install to use.
-  ROOT_DEV="$(basename "$(rootdev -s -d)")"
-  REMOVABLE="$(cat "/sys/block/${ROOT_DEV}/removable")" || :
-  if [ ${REMOVABLE:-0} -eq 0 ]; then
-    rm -rf "${FROM}"
-  fi
 end script