libct: fix staticcheck warning
libct: fix staticcheck warning

A new version of staticcheck (included into golangci-lint 1.46.2) gives
this new warning:

> libcontainer/factory_linux.go:230:59: SA9008: e refers to the result of a failed type assertion and is a zero value, not the value that was being type-asserted (staticcheck)
> 				err = fmt.Errorf("panic from initialization: %v, %s", e, debug.Stack())
> 				                                                      ^
> libcontainer/factory_linux.go:226:7: SA9008(related information): this is the variable being read (staticcheck)
> 			if e, ok := e.(error); ok {
> 			   ^

Apparently, this is indeed a bug. Fix by using a different name for a
new variable, so we can access the old one under "else".

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

opencontainers/runc,opencontainers/runc,opencontainers/runc,opencontainers/runc