security: tolerate invalid or unsupported public keys in PIB

Change-Id: I3c1dd9d3fe81d0895e2d1706f0b29a8e61940beb
diff --git a/tests/unit/security/pib/identity-container.t.cpp b/tests/unit/security/pib/identity-container.t.cpp
index 893f912..79daace 100644
--- a/tests/unit/security/pib/identity-container.t.cpp
+++ b/tests/unit/security/pib/identity-container.t.cpp
@@ -97,6 +97,13 @@
     BOOST_CHECK(container2.find(id1) == container2.end());
     BOOST_CHECK(container2.find(id2) != container2.end());
 
+    // removing the same identity again is a no-op
+    container2.remove(id1);
+    BOOST_CHECK_EQUAL(container2.size(), 1);
+    BOOST_CHECK_EQUAL(container2.m_identities.size(), 1);
+    BOOST_CHECK(container2.find(id1) == container2.end());
+    BOOST_CHECK(container2.find(id2) != container2.end());
+
     // remove another identity
     container2.remove(id2);
     BOOST_CHECK_EQUAL(container2.size(), 0);