macro: move 'boot' call into the 'Once' section

This also means boot function call chains must not cause circular
dependencies at all without a way to mitigate this in code. If this
should ever be a problem, we can move it out again, but this should
rather not be necessary.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

perlmod-macro/src/package.rs

@@ -127,9 +127,9 @@ impl Package {
 
                         #newxs
                     }
-                });
 
                     #boot
+                });
             }
         }
     }