Only set MPIs for signature types we can handle

TEXT signatures as those require canonicalized line endings which we
can't handle, and have no need for. Use a switch for the condition
in preparation for oncoming changes, an if only scales so far with
multiple choices.

rpmio/rpmpgp.c

@@ -549,17 +549,24 @@ static int pgpPrtSigParams(pgpTag tag, uint8_t pubkey_algo, uint8_t sigtype,
 {
     int rc = 1; /* assume failure */
     const uint8_t * pend = h + hlen;
-    int i;
+    int i, impl;
     pgpDigAlg sigalg = pgpSignatureNew(pubkey_algo);
 
+    switch (sigtype) {
+    case PGPSIGTYPE_BINARY:
+	impl = 1;
+	break;
+    default:
+	impl = 0;
+	break;
+    }
+
     for (i = 0; i < sigalg->mpis && pend - p >= 2; i++) {
 	int mpil = pgpMpiLen(p);
 	if (pend - p < mpil)
 	    break;
-	if (sigtype == PGPSIGTYPE_BINARY || sigtype == PGPSIGTYPE_TEXT) {
-	    if (sigalg->setmpi(sigalg, i, p))
+	if (impl && sigalg->setmpi(sigalg, i, p))
 		break;
-	}
 	p += mpil;
     }