title: Error when importing into a spark dataframe a mssql table named as an integer
body: <p>I have a table in MSSQL named as dbo.1table and I need to convert it into a dataframe and later on save it as an avro file but I can't even load it as dataframe.</p>
  
  <p>I tested my code with tables named with characters a-z and it works, I tried to convert the table name "toString()" and nothing has worked so far.
  I expect to have a dataframe and then save it as an avro file.
  Instead I have the folloiwng error:</p>
  
  <pre><code>val DFDimAccountOperator = spark.read.format("jdbc")
     .option("driver", "com.microsoft.sqlserver.jdbc.SQLServerDriver")
     .option("url", connection)
     .option("dbtable", "dbo.1table")
     .option("user", userId)
     .option("password", pwd).load() 
     DFDimAccountOperator.write.format("avro").save("conversionTypes/testinAVro13")
  
  Exception in thread "main" com.microsoft.sqlserver.jdbc.SQLServerException: Incorrect syntax near '.1'.    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDatabaseError(SQLServerException.java:262)
     at com.microsoft.sqlserver.jdbc.SQLServerStatement.getNextResult(SQLServerStatement.java:1621)
     at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.doExecutePreparedStatement(SQLServerPreparedStatement.java:592)
     at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement$PrepStmtExecCmd.doExecute(SQLServerPreparedStatement.java:522)
     at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:7194)
     at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:2935)
     at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeCommand(SQLServerStatement.java:248)
     at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeStatement(SQLServerStatement.java:223)
     at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.executeQuery(SQLServerPreparedStatement.java:444)
     at org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD$.resolveTable(JDBCRDD.scala:61)
     at org.apache.spark.sql.execution.datasources.jdbc.JDBCRelation$.getSchema(JDBCRelation.scala:210)
     at org.apache.spark.sql.execution.datasources.jdbc.JdbcRelationProvider.createRelation(JdbcRelationProvider.scala:35)
     at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:318)
     at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:223)
     at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:211)
     at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:167)
     at com.aon.ukbi.TomsExample$.runJdbcDatasetExample(TomsExample.scala:27)
     at com.aon.ukbi.TomsExample$.main(TomsExample.scala:16)
  </code></pre>