MXS-1896: Distinct LOAD DATA LOCAL INFILE from LOAD DATA INFILE

The two operations return different types of results and need to be
treated differently in order for them to be handled correctly in 2.2.

This fixes the unexpected internal state errors that happened in all 2.2
versions due to a wrong assumption made by readwritesplit. This fix is not
necessary for newer versions as the LOAD DATA LOCAL INFILE processing is
done with a simpler, and more robust, method.

maxscale-system-test/mxs1896_load_data_infile.cpp

@@ -0,0 +1,32 @@
+/**
+ * MXS-1896: LOAD DATA INFILE is mistaken for LOAD DATA LOCAL INFILE
+ *
+ * https://jira.mariadb.org/browse/MXS-1896
+ */
+
+#include "testconnections.h"
+
+int main(int argc, char** argv)
+{
+    TestConnections test(argc, argv);
+
+    test.set_timeout(30);
+    test.maxscales->connect();
+
+    test.try_query(test.maxscales->conn_rwsplit[0], "DROP TABLE IF EXISTS test.t1");
+    test.try_query(test.maxscales->conn_rwsplit[0], "CREATE TABLE test.t1(id INT)");
+    test.try_query(test.maxscales->conn_rwsplit[0], "INSERT INTO test.t1 VALUES (1), (2), (3)");
+    test.try_query(test.maxscales->conn_rwsplit[0], "SELECT * FROM test.t1 INTO OUTFILE '/tmp/test.csv'");
+    test.try_query(test.maxscales->conn_rwsplit[0], "LOAD DATA INFILE '/tmp/test.csv' INTO TABLE test.t1");
+    test.try_query(test.maxscales->conn_rwsplit[0], "DROP TABLE test.t1");
+
+    test.maxscales->disconnect();
+
+    // Clean up the generated files
+    for (int i = 0; i < 4; i++)
+    {
+        test.repl->ssh_node_f(i, true, "rm -f /tmp/test.csv");
+    }
+
+    return test.global_result;
+}