Prepared statement version check changes

Corrected version for which LIMIT supported PS + parameters (5.0.7 vs 5.1.0).

Added support for CALL in PS as of 5.5.3.

Fixed buffer overflow issue in CALL / LIMIT PS checks.
Fix MYSQL_DATA_TRUNCATED processing in server side prepared statements

Before this change if a server side prepared statement fetch returned MYSQL_DATA_TRUNCATED then no error was set yet the row wasn't returned.

This would cause reused statements where the subsequent calls returned more data to fail to return any data at all, without an error.

Now this is fixed also restroed server prepared statement testing in the chopblanks test which would previously fail.

Also fix compiler warning on buffer->is_null while I'm here.
Fix catalog tests for mysql 5.6+

mysql 5.6 removed the have_innodb variable, which caused all innodb tests to be skipped.

Replace this check with SHOW ENGINES one for 5.6+ so innodb tests are correctly run.
Prevent undef warning in DbiError