Fix saving/comparing mtime of files from remote for https://, file://, ftp://

This fixes refetching every time for non-http://

This reverts 7b846827.

Issue:	#977

libpkg/fetch.c

@@ -523,10 +523,10 @@ pkg_fetch_file_to_fd(struct pkg_repo *repo, const char *url, int dest, time_t *t
 
 	if (strcmp(u->scheme, "ssh") != 0) {
 		if (t != NULL && st.mtime != 0) {
-			if (st.mtime < *t) {
+			if (st.mtime <= *t) {
 				retcode = EPKG_UPTODATE;
 				goto cleanup;
-			} else if (strncmp(u->scheme, "http", 4) == 0)
+			} else
 				*t = st.mtime;
 		}
 		sz = st.size;