Fix lifecycle bug in MSSQL and Oracle rule (eclipse-vertx#1154)

The shared instance was started and stopped several times whereas it should happen only once. Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

Author: tsegismont

vertx-mssql-client/src/test/java/io/vertx/mssqlclient/junit/MSSQLRule.java

@@ -65,7 +65,7 @@ private boolean isNullOrEmpty(String connectionUri) {
 
  @Override
  protected void after() {
- if (isNullOrEmpty(System.getProperty("connection.uri")) || this != SHARED_INSTANCE) {
+ if (isNullOrEmpty(System.getProperty("connection.uri")) && this != SHARED_INSTANCE) {
  stopMSSQL();
  }
  }

vertx-oracle-client/src/test/java/io/vertx/oracleclient/test/junit/OracleRule.java

@@ -48,7 +48,7 @@ private boolean isNullOrEmpty(String s) {
 
  @Override
  protected void after() {
- if (isNullOrEmpty(System.getProperty("connection.uri")) || this != SHARED_INSTANCE) {
+ if (isNullOrEmpty(System.getProperty("connection.uri")) && this != SHARED_INSTANCE) {
  stopOracle();
  }
  }