jedi#debug_info: try/catch failures from s:init_python()

This is relevant for when using `:JediDebuginfo` in a broken setup,
where the call to `jedi#init_python()` in the autoload file throws an
error already (but `jedi#debug_info` is defined/loaded before already).

autoload/jedi.vim

@@ -186,7 +186,12 @@ endfunction
 
 function! jedi#debug_info() abort
     if s:python_version ==# 'null'
+        try
             call s:init_python()
+        catch
+            echohl WarningMsg | echom v:exception | echohl None
+            return
+        endtry
     endif
     if &verbose
       if &filetype !=# 'python'