scheduler: fix bugs related to changing code signing key

Two separate problems:
- a well-meaning change to remove compile warnings on 9 July 2013
  broke the reading of key files
- in the logic to scan old key files, we needed to use strip_whitespace()
  to remove the \n at end of file.

lib/crypt.cpp

@@ -213,8 +213,7 @@ int scan_key_hex(FILE* f, KEY* key, int size) {
     key->bits = num_bits;
     len = size - sizeof(key->bits);
     for (i=0; i<len; i++) {
-        fs = fscanf(f, "%2x", &n);
+        fscanf(f, "%2x", &n);
-        if (fs != 1) return ERR_NULL;
         key->data[i] = n;
     }
     fs = fscanf(f, ".");

sched/handle_request.cpp

@@ -863,6 +863,7 @@ bool send_code_sign_key(char* code_sign_key) {
                     );
                     return false;
                 }
+                strip_whitespace(oldkey);
                 if (!strcmp(oldkey, g_request->code_sign_key)) {
                     // We've found the client's key.
                     // Get the signature for the new key.
@@ -883,6 +884,9 @@ bool send_code_sign_key(char* code_sign_key) {
                         free(oldkey);
                         return false;
                     } else {
+                        log_messages.printf(MSG_NORMAL,
+                            "sending new code sign key and signature\n"
+                        );
                         safe_strcpy(g_reply->code_sign_key, code_sign_key);
                         safe_strcpy(g_reply->code_sign_key_signature, signature);
                         free(signature);