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/script_tests.cpp

@@ -1199,7 +1199,7 @@ SignatureData CombineSignatures(const CTxOut& txout, const CMutableTransaction&
 BOOST_AUTO_TEST_CASE(script_combineSigs)
 {
     // Test the ProduceSignature's ability to combine signatures function
-    CBasicKeyStore keystore;
+    FillableSigningProvider keystore;
     std::vector<CKey> keys;
     std::vector<CPubKey> pubkeys;
     for (int i = 0; i < 3; i++)