[VOCABULARIES] removed type restriction for qcode
[VOCABULARIES] removed type restriction for qcode

qcode should be string, but it is sometimes used as int (in "priority"
and "urgency"). This patch restore former behaviour of not restricting
qcode type, to avoid breaking existing use of this vocabulary and to fix
"priority" and "urgency" use issues.

SDESK-2922

superdesk/superdesk-core,mdhaman/superdesk-core,mdhaman/superdesk-core,superdesk/superdesk-core,petrjasek/superdesk-core,superdesk/superdesk-core,mugurrus/superdesk-core,ioanpocol/superdesk-core,petrjasek/superdesk-core,ioanpocol/superdesk-core,mdhaman/superdesk-core,petrjasek/superdesk-core,mugurrus/superdesk-core,superdesk/superdesk-core,mugurrus/superdesk-core,ioanpocol/superdesk-core,petrjasek/superdesk-core