Initialise Alert's method to an empty string
Initialise Alert's method to an empty string

The change prevents NullPointerException when testing for equality,
doing comparisons or obtaining the hash code if the alert no longer has
a message (thus the method was not being set to a non-null value).

JordanGS/zaproxy,Harinus/zaproxy,psiinon/zaproxy,gmaran23/zaproxy,gmaran23/zaproxy,rajiv65/zaproxy,meitar/zaproxy,Harinus/zaproxy,NVolcz/zaproxy,meitar/zaproxy,psiinon/zaproxy,meitar/zaproxy,gsavastano/zaproxy,NVolcz/zaproxy,NVolcz/zaproxy,zapbot/zaproxy,kingthorin/zaproxy,meitar/zaproxy,JordanGS/zaproxy,gsavastano/zaproxy,Ali-Razmjoo/zaproxy,zapbot/zaproxy,Harinus/zaproxy,meitar/zaproxy,JordanGS/zaproxy,Ali-Razmjoo/zaproxy,meitar/zaproxy,zaproxy/zaproxy,meitar/zaproxy,JordanGS/zaproxy,zapbot/zaproxy,NVolcz/zaproxy,gmaran23/zaproxy,kingthorin/zaproxy,psiinon/zaproxy,Ali-Razmjoo/zaproxy,Harinus/zaproxy,Ali-Razmjoo/zaproxy,kingthorin/zaproxy,gmaran23/zaproxy,zaproxy/zaproxy,gmaran23/zaproxy,thc202/zaproxy,JordanGS/zaproxy,rajiv65/zaproxy,kingthorin/zaproxy,NVolcz/zaproxy,rajiv65/zaproxy,rajiv65/zaproxy,NVolcz/zaproxy,thc202/zaproxy,gsavastano/zaproxy,zapbot/zaproxy,psiinon/zaproxy,thc202/zaproxy,rajiv65/zaproxy,zapbot/zaproxy,psiinon/zaproxy,zapbot/zaproxy,Harinus/zaproxy,gmaran23/zaproxy,Ali-Razmjoo/zaproxy,psiinon/zaproxy,zaproxy/zaproxy,rajiv65/zaproxy,zaproxy/zaproxy,gsavastano/zaproxy,Ali-Razmjoo/zaproxy,gmaran23/zaproxy,zaproxy/zaproxy,Ali-Razmjoo/zaproxy,kingthorin/zaproxy,gsavastano/zaproxy,Harinus/zaproxy,thc202/zaproxy,thc202/zaproxy,rajiv65/zaproxy,kingthorin/zaproxy,gsavastano/zaproxy,NVolcz/zaproxy,meitar/zaproxy,zaproxy/zaproxy,JordanGS/zaproxy,zaproxy/zaproxy,zapbot/zaproxy,kingthorin/zaproxy,JordanGS/zaproxy,psiinon/zaproxy,thc202/zaproxy,gsavastano/zaproxy,thc202/zaproxy,Harinus/zaproxy