scripted-diff: rename CBasicKeyStore to FillableSigningProvider

-BEGIN VERIFY SCRIPT-
git grep -l "CBasicKeyStore" | xargs sed -i -e 's/CBasicKeyStore/FillableSigningProvider/g'
-END VERIFY SCRIPT-

src/test/txvalidationcache_tests.cpp

@@ -161,7 +161,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup)
     CScript p2pkh_scriptPubKey = GetScriptForDestination(PKHash(coinbaseKey.GetPubKey()));
     CScript p2wpkh_scriptPubKey = GetScriptForWitness(p2pkh_scriptPubKey);
 
-    CBasicKeyStore keystore;
+    FillableSigningProvider keystore;
     BOOST_CHECK(keystore.AddKey(coinbaseKey));
     BOOST_CHECK(keystore.AddCScript(p2pk_scriptPubKey));