IMPALA-1025: Use converse of data source predicate operators if expr has val before slot

Change-Id: I31790c037e2fa9af7b80c01014f7507ba5053e63
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2808
Reviewed-by: Marcel Kornacker <marcel@cloudera.com>
Tested-by: jenkins
IMPALA-1022: Handle cases where in Parquet the expected number of rows in metadata is wrong

There are cases of Parquet files where the metadata indicate wrong number of rows for
these files. The parquet-scanner until now was not reporting any problem in this case.
Instead it was reading as long as there where values for the read columns.
But with IMPALA-1016 we are now reading at most as many rows as the rows per metadata.
With this patch, the parquet-scanner, right before it finishes scannings, checks whether
it read the expected number of rows (taken from metadata). In cases where the actual
number of rows read is less than or greater than the expected number, it either aborts
or logs an error.

Change-Id: Ie6a66a38e8912730bf04762e6526ec1cadb2bcdc
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2755
Reviewed-by: Ippokratis Pandis <ipandis@cloudera.com>
Tested-by: jenkins
CDH-19184: Impala should show impersonated user (if there is one) rather than connected user

Currently, we always display the 'User' as the connected user in the debug webpage and
runtime profiles. This is confusing when impersonation + authorization is enabled because
there is not an easy way to find the impersonated user other than looking at the audit
log records. This change does the following:
* Updates the "User" field in the runtime profile to show the "effective user".
  The effective user is the connected user if there is no impersonated user,
  otherwise it is the impersonated user. This should help CM display the correct user
  as well.
* Add two new fields in the runtime profile "Connected User" & "Impersonated User"
  to make it easier to tell which user is which.
* Update the /queries debug webpage to show the effective user rather than the
  connected user.

Change-Id: I639de6738242d2c378e785271a72257301a53ade
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2863
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: jenkins