Fix pki-server subsystem-cert-export

Solve the pki-server subsystem-cert-export error when trying to export a
CSR.

Fix bz-2276139

base/server/python/pki/server/subsystem.py

@@ -380,6 +380,13 @@ def get_cert_info(self, tag):
         cert['nickname'] = self.config.get('%s.%s.nickname' % (self.name, tag))
         cert['token'] = self.config.get('%s.%s.tokenname' % (self.name, tag))
         cert['certusage'] = self.config.get('%s.cert.%s.certusage' % (self.name, tag))
+        try:
+            csr_file = self.csr_file(tag)
+            with open(csr_file, "r", encoding='utf-8') as f:
+                request = f.read()
+            cert['request'] = pki.nssdb.convert_csr(request, 'pem', 'base64')
+        except  IOError:
+            logger.error('Cannot find %s csr', tag)
 
         return cert