libsysutils: Fix some bugs in NetlinkListener and NetlinkEvent

Signed-off-by: San Mehat <san@android.com>
diff --git a/libsysutils/src/NetlinkEvent.cpp b/libsysutils/src/NetlinkEvent.cpp
index 5573c3f..5f959a7 100644
--- a/libsysutils/src/NetlinkEvent.cpp
+++ b/libsysutils/src/NetlinkEvent.cpp
@@ -28,6 +28,9 @@
 
 NetlinkEvent::NetlinkEvent() {
     mAction = NlActionUnknown;
+    memset(mParams, 0, sizeof(mParams));
+    mPath = NULL;
+    mSubsystem = NULL;
 }
 
 NetlinkEvent::~NetlinkEvent() {