Remove more dead code from minzip.

I've added explanatory comments to mzExtractRecursive because
that function will live on as a utility even after we move the
zip format related logic to libziparchive.

bug: 19472796

(cherry-picked from commit c9ccdfd7a42de08c47ab771b94dc5b9d1f957b95)

Change-Id: I8b7fb6fa3eafb2e7ac080ef7a7eceb691b252d8a
diff --git a/minzip/Zip.h b/minzip/Zip.h
index 54eab32..a2b2c26 100644
--- a/minzip/Zip.h
+++ b/minzip/Zip.h
@@ -143,9 +143,12 @@
     const ZipEntry *pEntry, unsigned char* buffer);
 
 /*
- * Inflate all entries under zipDir to the directory specified by
+ * Inflate all files under zipDir to the directory specified by
  * targetDir, which must exist and be a writable directory.
  *
+ * Directory entries and symlinks are not extracted.
+ *
+ *
  * The immediate children of zipDir will become the immediate
  * children of targetDir; e.g., if the archive contains the entries
  *
@@ -160,21 +163,15 @@
  *     /tmp/two
  *     /tmp/d/three
  *
- * flags is zero or more of the following:
- *
- *     MZ_EXTRACT_FILES_ONLY - only unpack files, not directories or symlinks
- *     MZ_EXTRACT_DRY_RUN - don't do anything, but do invoke the callback
- *
  * If timestamp is non-NULL, file timestamps will be set accordingly.
  *
  * If callback is non-NULL, it will be invoked with each unpacked file.
  *
  * Returns true on success, false on failure.
  */
-enum { MZ_EXTRACT_FILES_ONLY = 1, MZ_EXTRACT_DRY_RUN = 2 };
 bool mzExtractRecursive(const ZipArchive *pArchive,
         const char *zipDir, const char *targetDir,
-        int flags, const struct utimbuf *timestamp,
+        const struct utimbuf *timestamp,
         void (*callback)(const char *fn, void*), void *cookie,
         struct selabel_handle *sehnd);