rules: fix empty COMMITCOUNT/AUTORELEASE

Packages that are in-tree only often lack a PKG_VERSION and only use the
PKG_RELEASE to mark changes. Using COMMITCOUNT/AUTORELEASE variables
causes an issue as both variables are empty during the metadata DUMP
phase.

Instead of leaving these variables empty and causing an error message
like below, set the variables to 0 during dumping. On actual building
the variable is evaluated causing in a value above 0.

ERROR: please fix package/utils/px5g-wolfssl/Makefile - \
	see logs/package/utils/px5g-wolfssl/dump.txt for details

Makefile:48: *** Package/px5g-wolfssl is missing the VERSION field.  Stop.

Reported-by: Daniel Golle <daniel@makrotopia.org>
Reported-by: Stijn Segers <foss@volatilesystems.org>
Reported-by: Stijn Tintel <stijn@linux-ipv6.be>
Signed-off-by: Paul Spooren <mail@aparcar.org>

rules.mk

@@ -431,8 +431,8 @@ $(shell \
 )
 endef
 
-COMMITCOUNT = $(if $(DUMP),,$(call commitcount))
-AUTORELEASE = $(if $(DUMP),,$(call commitcount,1))
+COMMITCOUNT = $(if $(DUMP),0,$(call commitcount))
+AUTORELEASE = $(if $(DUMP),0,$(call commitcount,1))
 
 all:
 FORCE: ;