Corrected variable edited field for blood dna. Was dna, not b_dna like it should be.
Fixed bad reference to active 1 in the medical computer's DNA field inputs.
Ported blank field patch to Computer3 systems
Merge branch 'dna_field_fix' into computer3_text_field_fix

Conflicts:
	code/WorkInProgress/computer3/computers/medical.dm
Merge pull request #5848 from JimTheCactus/computer3_text_field_fix

DNA Field Fix and Field Validation