Some variables need default value

plugin/vimsnippets.vim

@@ -3,6 +3,19 @@ if exists("b:done_vimsnippets")
 endif
 let b:done_vimsnippets = 1
 
+" Some variables need default value
+if !exists("g:snips_author")
+    let g:snips_author = "yourname"
+endif
+
+if !exists("g:snips_email")
+    let g:snips_email = "yourname@email.com"
+endif
+
+if !exists("g:snips_github")
+    let g:snips_github = "https://github.com/yourname"
+endif
+
 " Expanding the path is not needed on Vim 7.4
 if &cp || version >= 704
     finish