[2479] Remove unnecessary assignment.

tests/tools/perfdhcp/tests/testdata/Makefile.am

@@ -4,7 +4,5 @@ SUBDIRS = .
 # unit tests and have to be removed.
 CLEANFILES = test1.hex test2.hex test3.hex test4.hex test5.hex
 
-perfdhcpdir = $(pkgdatadir)
-
 EXTRA_DIST = discover-example.hex request4-example.hex
 EXTRA_DIST += solicit-example.hex request6-example.hex