dpkg-split: Fix short lived memory leaks in mksplit()

Warned-by: coverity

debian/changelog

@@ -7,6 +7,7 @@ dpkg (1.17.9) UNRELEASED; urgency=low
   * Do not leak long tar names on bogus or truncated archives.
   * Do not leak the filepackages iterator when a directory is used by other
     packages.
+  * Fix short lived memory leaks in «dpkg-split --split».
 
   [ Updated scripts translations ]
   * French (Steve Petruzzello). Closes: #746350

dpkg-split/split.c

@@ -234,6 +234,10 @@ mksplit(const char *file_src, const char *prefix, off_t maxpartsize,
 	varbuf_destroy(&partname);
 	varbuf_destroy(&partmagic);
 
+	free(package);
+	free(version);
+	free(arch);
+
 	free(prefixdir);
 	free(msdos_prefix);