update-kernel: Make UPDATE_KERNEL_SYS_FLAVOUR try to fake 'uname -r'

This is for debugging purposes to test upgrade from 'std-def'

Since I use the archive for testing on a host with a much newer kernel, it
cannot find a flavor to upgrade from 6.11 if the archive only has 6.10.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>

update-kernel

@@ -398,6 +398,11 @@ fi
 # set kernel flavour. if not defined with -t option, use current
 if [ -n "$UPDATE_KERNEL_SYS_FLAVOUR" ]; then
 	current_kernel_flavour=$UPDATE_KERNEL_SYS_FLAVOUR
+	ur=$(rpm -q --qf '%{VERSION}-%{NAME}-%{RELEASE}\n' \
+		"kernel-image-$UPDATE_KERNEL_SYS_FLAVOUR" 2>/dev/null |
+		sort -V | tail -1 | sed 's/kernel-image-//')
+	[ -n "$ur" ] && uname_r=$ur
+	unset ur
 else
 	current_kernel_flavour=$uname_r
 	current_kernel_flavour="${current_kernel_flavour#*-}"