creator: Change rootfs description to match cmdline argument

This changes the log entry from squashfs+ext4/erofs+ext4 to
squashfs-ext4/erofs-ext4 which matches the cmdline argument passed to
--rootfs-type, making the naming of it more consistent.

src/pylorax/creator.py

@@ -227,15 +227,15 @@ def make_runtime(opts, mount_dir, work_dir, size=None):
                   compression=compression, compressargs=compressargs)
     elif opts.rootfs_type == "squashfs-ext4":
         compression, compressargs = squashfs_args(opts)
-        log.info("Creating a squashfs+ext4 runtime")
+        log.info("Creating a squashfs-ext4 runtime")
         return rb.create_ext4_runtime(joinpaths(work_dir, RUNTIME), size=size,
                   compression=compression, compressargs=compressargs)
     elif opts.rootfs_type == "erofs":
         log.info("Creating a erofs only runtime")
         return rb.create_erofs_runtime(joinpaths(work_dir, RUNTIME), size=size,
                   compression="lzma")
     elif opts.rootfs_type == "erofs-ext4":
-        log.info("Creating a erofs+ext4 runtime")
+        log.info("Creating a erofs-ext4 runtime")
         return rb.create_erofs_ext4_runtime(joinpaths(work_dir, RUNTIME), size=size,
                   compression="lzma")
     else: