Fix issues type with ldparser.

Sometime, in the most general case, the message is a warning, and not an error.
Two cases:
 * linker returning a message like this: 'filename: warning: description'
 * uic returns messages like this: 'Warning: description'

Change-Id: I2babe1de2753ea8b2871419f1b1405eb7ae73d48
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>