[incremental] fix x86 native lib extraction

Test: atest CtsIncrementalInstallHostTestCases
BUG: 168138334
Change-Id: I7b76afbd88cf3f38c1527c9c917ce179e0bde589
diff --git a/services/incremental/IncrementalService.cpp b/services/incremental/IncrementalService.cpp
index e8bf468..bbcb312 100644
--- a/services/incremental/IncrementalService.cpp
+++ b/services/incremental/IncrementalService.cpp
@@ -1468,7 +1468,7 @@
     // Need a shared pointer: will be passing it into all unpacking jobs.
     std::shared_ptr<ZipArchive> zipFile(zipFileHandle, [](ZipArchiveHandle h) { CloseArchive(h); });
     void* cookie = nullptr;
-    const auto libFilePrefix = path::join(constants().libDir, abi);
+    const auto libFilePrefix = path::join(constants().libDir, abi) + "/";
     if (StartIteration(zipFile.get(), &cookie, libFilePrefix, constants().libSuffix)) {
         LOG(ERROR) << "Failed to start zip iteration for " << apkFullPath;
         return false;