If code completetion is deselected, don't add keywords or key commands.

To prevent a crash in shared ngspice

src/frontend/parser/complete.c

@@ -461,6 +461,9 @@ cp_addcomm(char *word, long int bits0, long int bits1, long int bits2, long int
 {
     struct ccom *cc;
 
+    if(cp_nocc)
+        return;
+
     cc = clookup(word, &commands, FALSE, TRUE);
     cc->cc_invalid = 0;
     cc->cc_kwords[0] = bits0;
@@ -490,6 +493,9 @@ cp_addkword(int kw_class, char *word)
 {
     struct ccom *cc;
 
+    if(cp_nocc)
+        return;
+
     if ((kw_class < 1) || (kw_class >= NCLASSES)) {
         fprintf(cp_err, "cp_addkword: Internal Error: bad class %d\n",
                 kw_class);