Harmonize the error handling codepath

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7121)

crypto/dh/dh_lib.c

@@ -83,12 +83,14 @@ DH *DH_new_method(ENGINE *engine)
 
     if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {
         DHerr(DH_F_DH_NEW_METHOD, ERR_R_INIT_FAIL);
-err:
-        DH_free(ret);
-        ret = NULL;
+        goto err;
     }
 
     return ret;
+
+ err:
+    DH_free(ret);
+    return NULL;
 }
 
 void DH_free(DH *r)

crypto/dsa/dsa_lib.c

@@ -90,12 +90,14 @@ DSA *DSA_new_method(ENGINE *engine)
 
     if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {
         DSAerr(DSA_F_DSA_NEW_METHOD, ERR_R_INIT_FAIL);
-err:
-        DSA_free(ret);
-        ret = NULL;
+        goto err;
     }
 
     return ret;
+
+ err:
+    DSA_free(ret);
+    return NULL;
 }
 
 void DSA_free(DSA *r)

crypto/ec/ec_kmeth.c

@@ -119,7 +119,7 @@ EC_KEY *EC_KEY_new_method(ENGINE *engine)
     }
     return ret;
 
-err:
+ err:
     EC_KEY_free(ret);
     return NULL;
 }

crypto/rsa/rsa_lib.c

@@ -97,7 +97,7 @@ RSA *RSA_new_method(ENGINE *engine)
 
     return ret;
 
-err:
+ err:
     RSA_free(ret);
     return NULL;
 }