security: tolerate invalid or unsupported public keys in PIB

Change-Id: I3c1dd9d3fe81d0895e2d1706f0b29a8e61940beb
diff --git a/tests/unit/security/pib/key-container.t.cpp b/tests/unit/security/pib/key-container.t.cpp
index fac7739..a7d29ef 100644
--- a/tests/unit/security/pib/key-container.t.cpp
+++ b/tests/unit/security/pib/key-container.t.cpp
@@ -103,6 +103,13 @@
     BOOST_CHECK(container2.find(id1Key1Name) == container2.end());
     BOOST_CHECK(container2.find(id1Key2Name) != container2.end());
 
+    // removing the same key again is a no-op
+    container2.remove(id1Key1Name);
+    BOOST_CHECK_EQUAL(container2.size(), 1);
+    BOOST_CHECK_EQUAL(container2.m_keys.size(), 1);
+    BOOST_CHECK(container2.find(id1Key1Name) == container2.end());
+    BOOST_CHECK(container2.find(id1Key2Name) != container2.end());
+
     // remove another key
     container2.remove(id1Key2Name);
     BOOST_CHECK_EQUAL(container2.size(), 0);