Changed the condition to consider negative value for PID.

In this test case inserted PID can be negative, causing File.exist() to become false, and thus results in error.

We modified the test case so that it considers negative value of PID.
diff --git a/tests/tests/security/src/android/security/cts/VoldExploitTest.java b/tests/tests/security/src/android/security/cts/VoldExploitTest.java
index df58a2c..df5e58a 100644
--- a/tests/tests/security/src/android/security/cts/VoldExploitTest.java
+++ b/tests/tests/security/src/android/security/cts/VoldExploitTest.java
@@ -172,7 +172,7 @@
         for (List<String> i : netlink) {
             // The PID is in column 3
             int pid = Integer.decode(i.get(2));
-            if (pid != 0) {
+            if (pid > 0) {
                 retval.add(pid);
             }
         }