LU-16391 build: update version to 1.46.6-wc1

LU-16391 build: update version to 1.46.6-wc1

Update configure.ac to separate Version from Release in the .spec.in
files so that RPM building doesn't choke if a '-' is in the version.
Add these changes into configure also, so they are immediately used.

Change-Id: I6cbf6efa25175f9cebeb349d28e1e8a565b4cb74
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/tools/e2fsprogs/+/49421
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>