[SPARK-14185][SQL][Minor] Make indentation of debug log for generated code proper

[sarutak]

What changes were proposed in this pull request?

The indentation of debug log output by CodeGenerator is weird.
The first line of the generated code should be put on the next line of the first line of the log message.

16/03/28 11:10:24 DEBUG CodeGenerator: /* 001 */                                                                                                              
/* 002 */ public java.lang.Object generate(Object[] references) {
/* 003 */   return new SpecificSafeProjection(references); 
...

After this patch is applied, we get debug log like as follows.

16/03/28 10:45:50 DEBUG CodeGenerator:                                                 
/* 001 */ 
/* 002 */ public java.lang.Object generate(Object[] references) {
/* 003 */   return new SpecificSafeProjection(references);
...

How was this patch tested?

Ran some jobs and checked debug logs.

[SparkQA]

Test build #54292 has finished for PR 11990 at commit 49ac4c8.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[rxin]

Thanks - merging in master.