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/wallet/test/wallet_tests.cpp

@@ -488,7 +488,7 @@ static size_t CalculateNestedKeyhashInputSize(bool use_max_sig)
     CScript script_pubkey = CScript() << OP_HASH160 << std::vector<unsigned char>(script_id.begin(), script_id.end()) << OP_EQUAL;
 
     // Add inner-script to key store and key to watchonly
-    CBasicKeyStore keystore;
+    FillableSigningProvider keystore;
     keystore.AddCScript(inner_script);
     keystore.AddKeyPubKey(key, pubkey);