Take care of minor schema differences between D6 and D7 versions

After upgrading quicktabs from a D6 to the D7 version (using these patches, which should be committed soon, by the way: #1444418: Field 'style' doesn't have a default value during D6 to D7 upgrade → #1444376: Unknown column 'renderer' in 'field list' error during D6 to D7 upgrade → ), I see that there are some minor schema differences that aren't accounted for:

column hide_empty_tabs - difference on: size
declared: array('description' => 'TODO: please describe this field!', 'type' => 'int', 'unsigned' => TRUE, 'size' => 'tiny', 'not null' => TRUE, 'default' => 0)
actual: array('description' => 'TODO: please describe this field!', 'type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0)
column default_tab - differences on: size, default
declared: array('description' => 'TODO: please describe this field!', 'type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0)
actual: array('description' => 'TODO: please describe this field!', 'type' => 'int', 'unsigned' => TRUE, 'size' => 'tiny', 'not null' => TRUE)
column renderer - difference on: default
declared: array('description' => 'TODO: please describe this field!', 'type' => 'varchar', 'length' => 255, 'not null' => TRUE)
actual: array('description' => 'The rendering mechanism.', 'type' => 'varchar', 'length' => '255', 'not null' => TRUE, 'default' => 'quicktabs')

They should be taken care of in a new update function. Patch attached.