cert_create: remove unneeded initializers

These variables store return values of functions.  Remove all of
meaningless initializers.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/tools/cert_create/src/key.c b/tools/cert_create/src/key.c
index 47c152c..ce0e4da 100644
--- a/tools/cert_create/src/key.c
+++ b/tools/cert_create/src/key.c
@@ -62,7 +62,7 @@
 
 static int key_create_rsa(key_t *key)
 {
-	RSA *rsa = NULL;
+	RSA *rsa;
 
 	rsa = RSA_generate_key(RSA_KEY_BITS, RSA_F4, NULL, NULL);
 	if (rsa == NULL) {
@@ -83,7 +83,7 @@
 #ifndef OPENSSL_NO_EC
 static int key_create_ecdsa(key_t *key)
 {
-	EC_KEY *ec = NULL;
+	EC_KEY *ec;
 
 	ec = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
 	if (ec == NULL) {
@@ -132,8 +132,8 @@
 
 int key_load(key_t *key, unsigned int *err_code)
 {
-	FILE *fp = NULL;
-	EVP_PKEY *k = NULL;
+	FILE *fp;
+	EVP_PKEY *k;
 
 	if (key->fn) {
 		/* Load key from file */
@@ -162,7 +162,7 @@
 
 int key_store(key_t *key)
 {
-	FILE *fp = NULL;
+	FILE *fp;
 
 	if (key->fn) {
 		fp = fopen(key->fn, "w");
@@ -185,7 +185,6 @@
 {
 	cmd_opt_t cmd_opt;
 	key_t *key;
-	int rc = 0;
 	unsigned int i;
 
 	for (i = 0; i < num_keys; i++) {
@@ -200,12 +199,12 @@
 		}
 	}
 
-	return rc;
+	return 0;
 }
 
 key_t *key_get_by_opt(const char *opt)
 {
-	key_t *key = NULL;
+	key_t *key;
 	unsigned int i;
 
 	/* Sequential search. This is not a performance concern since the number