[BUG] Field not all should be Upper.

[IBAS0742]

	fieldName = strings.ToUpper(fieldName)
	// sometime fieldName is Camel-Case

I use this code to deal with the geotiff's attribute table, and I found the field name "Value" can not be found, but the error's message is the field name "VALUE" can not be found.

After I comment the code, I got the right result.