vndk-def: Add path separator to the end of pattern.

This commit adds path separator to the end of regular expression pattern
for alternating path, which were specified with --system-dir-as-vendor
and --vendor-dir-as-system.  This prevents us from treating
/system/bin/hwservicemanager as vendor module.

Test: Run vndk_definition_tool.py against AOSP images.

Change-Id: If18be210b8e72d662de8bc7e30af27015c72eb9b