NativeLibraryHelper: Minor fixes

Skip over directories when iterating library files. Ensure correct
temp file naming.

Bug: 33668201
Test: m
Test: Device boots
Test: Manual: Install debuggable and non-debuggable apps
Change-Id: I2f0547e965d9a0c478e333a13b2db02f4eedac2c

core/jni/com_android_internal_content_NativeLibraryHelper.cpp

@@ -243,7 +243,7 @@ copyFileIfChanged(JNIEnv *env, void* arg, ZipFileRO* zipFile, ZipEntryRO zipEntr
         return INSTALL_FAILED_INTERNAL_ERROR;
     }
 
-    *(localFileName + nativeLibPath.size()) = '/';
+    *(localTmpFileName + nativeLibPath.size()) = '/';
 
     if (strlcpy(localTmpFileName + nativeLibPath.size(), TMP_FILE_PATTERN,
                     TMP_FILE_PATTERN_LEN - nativeLibPath.size()) != TMP_FILE_PATTERN_LEN) {
@@ -344,6 +344,11 @@ public:
             const char* lastSlash = strrchr(fileName, '/');
             ALOG_ASSERT(lastSlash != NULL, "last slash was null somehow for %s\n", fileName);
 
+            // Skip directories.
+            if (*(lastSlash + 1) == 0) {
+                continue;
+            }
+
             // Make sure the filename is safe.
             if (!isFilenameSafe(lastSlash + 1)) {
                 continue;