[ruby/openssl] pkcs7: fix memory leak in error path of PKCS7.new and .read_smime

A follow-up to commit https://github.com/ruby/openssl/commit/27e11f2d1dcd and https://github.com/ruby/openssl/commit/07eceb7f6326. The PKCS7 object
must be freed before raising an exception.

https://github.com/ruby/openssl/commit/172eee4665

ext/openssl/ossl_pkcs7.c

@@ -167,8 +167,10 @@ ossl_pkcs7_s_read_smime(VALUE klass, VALUE arg)
     BIO_free(in);
     if (!pkcs7)
         ossl_raise(ePKCS7Error, "Could not parse the PKCS7");
-    if (!pkcs7->d.ptr)
+    if (!pkcs7->d.ptr) {
+        PKCS7_free(pkcs7);
         ossl_raise(ePKCS7Error, "No content in PKCS7");
+    }
 
     data = out ? ossl_membio2str(out) : Qnil;
     SetPKCS7(ret, pkcs7);
@@ -348,8 +350,10 @@ ossl_pkcs7_initialize(int argc, VALUE *argv, VALUE self)
     BIO_free(in);
     if (!p7)
         ossl_raise(rb_eArgError, "Could not parse the PKCS7");
-    if (!p7->d.ptr)
+    if (!p7->d.ptr) {
+        PKCS7_free(p7);
         ossl_raise(rb_eArgError, "No content in PKCS7");
+    }
 
     RTYPEDDATA_DATA(self) = p7;
     PKCS7_free(p7_orig);