[master] Update various .gitignore files

src/bin/dhcp4/.gitignore

@@ -1,4 +1,6 @@
 /b10-dhcp4
+/b10-dhcp4.8
+/dhcp4_messages.cc
+/dhcp4_messages.h
 /spec_config.h
 /spec_config.h.pre
-/b10-dhcp4.8

src/bin/dhcp6/.gitignore

@@ -1,11 +1,6 @@
-*~
-Makefile
-Makefile.in
-*.o
-.deps
-.libs
-b10-dhcp6
-spec_config.h
-spec_config.h.pre
-tests/dhcp6_unittests
+/b10-dhcp6
 /b10-dhcp6.8
+/dhcp6_messages.cc
+/dhcp6_messages.h
+/spec_config.h
+/spec_config.h.pre

src/bin/dhcp6/tests/.gitignore

@@ -0,0 +1 @@
+/dhcp6_unittests

tests/tools/perfdhcp/.gitignore

@@ -1 +1,2 @@
 /perfdhcp
+/perfdhcp2