[YSQL] YSQL sampleapps bugs

[rao-vasireddy]

1. SqlInserts - fails with "ybdemo_database does not exist"
2. SqlUpdates - is not idempotent. fails with " database "ybdemo_database" already exists" the second you run the app
3. SqlSecondaryIndex - fails with
   Exception in thread "main" org.postgresql.util.PSQLException: ERROR: syntax error at or near "NOT"
   Position: 20
   at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2433)
   at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2178)
   at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:306)
   at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:441)
   at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:365)
   at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:307)
   at org.postgresql.jdbc.PgStatement.executeCachedSql(PgStatement.java:293)
   at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:270)
   at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:266)
4. SqlSnapshotTxns fails with the same error as Includes maven wrapper #3 above