Replace '-' in kernel version with '_'

Removing the '-' results in hard to read filenames such as:
kernel-2.6.35.2000042g76e4caf-28.x86_64.rpm

kernel-2.6.35.2_000042_g76e4caf-28.x86_64.rpm is easier to
read.

Signed-off-by: Arun Sharma <asharma@fb.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/scripts/package/mkspec b/scripts/package/mkspec
index e1c1d5b..ed8b6a8 100755
--- a/scripts/package/mkspec
+++ b/scripts/package/mkspec
@@ -22,7 +22,7 @@
 fi
 
 PROVIDES="$PROVIDES kernel-$KERNELRELEASE"
-__KERNELRELEASE=`echo $KERNELRELEASE | sed -e "s/-//g"`
+__KERNELRELEASE=`echo $KERNELRELEASE | sed -e "s/-/_/g"`
 
 echo "Name: kernel"
 echo "Summary: The Linux Kernel"