Need better error reporting -- follow up on MCOL-698

Build tested: 1.1.0-1 GitHub source

[root@localhost mariadb-columnstore-server]# git show
commit bd13090ea83f35f125c1d103204c0070ae0f721b
Merge: abc4c52 f63ee30
Author: dhall-InfiniDB <david.hall@mariadb.com>
Date: Thu May 4 11:01:51 2017 -0500
Merge pull request #46 from mariadb-corporation/MCOL-693
MCOL-693 Fix non-string SP parameters
[root@localhost mariadb-columnstore-server]# cd mariadb-columnstore-engine/
[root@localhost mariadb-columnstore-engine]# git show
commit a6dfc3c366c861d5777a9931e18f594405e4aab6
Merge: 1c2a8fc 00cd7f4
Author: dhall-InfiniDB <david.hall@mariadb.com>
Date: Thu May 4 10:33:30 2017 -0500
Merge pull request #168 from mariadb-corporation/MCOL-698
MCOL-698 Fix joiner for LONGTEXT

When joining two BLOB/LONGBLOB columns, an internal error occurred. We should handle the condition better, instead of just return an internal error. If such joins joins are not reasonable and it is not supported, then we need failed the query and indicate as such.

Please refer to MCOL-698 for more info