Properly initialize the clone options

libgit2 provides an initialization function to set sane defaults. Use
that instead of setting the version by hand, as that's not the only
thing it does.

Using C.git_clone_init_options() sets the checkout strategy to SAFE,
which will checkout the files after the clone, instead of the implicit
NONE which we're setting by hand.

This fixes #425,

Author: carlosmn

pygit2/__init__.py

@@ -160,7 +160,7 @@ def clone_repository(
     remote_name_ref = ffi.new('char []', to_bytes(remote_name))
     opts.remote_name = remote_name_ref
 
-    opts.version = 1
+    C.git_clone_init_options(opts, 1)
     opts.ignore_cert_errors = ignore_cert_errors
     opts.bare = bare
     opts.remote_callbacks.version = 1

pygit2/decl.h

@@ -353,6 +353,8 @@ typedef struct git_clone_options {
 	git_signature *signature;
 } git_clone_options;
 
+int git_clone_init_options(git_clone_options *opts, unsigned int version);
+
 int git_clone(git_repository **out,
 	const char *url,
 	const char *local_path,