Fix typos

After this change:
```
codespell --builtin clear,rare,en-GB_to_en-US -d --count --skip
"./subprojects/*,./.git" .
0
```

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I7bc4c94facdd366dea91e456e7ef8a0b05532b99
diff --git a/csr.cpp b/csr.cpp
index dc26522..c93a487 100644
--- a/csr.cpp
+++ b/csr.cpp
@@ -57,7 +57,7 @@
         {
             std::fclose(fp);
         }
-        log<level::ERR>("ERROR occured while reading CSR file",
+        log<level::ERR>("ERROR occurred while reading CSR file",
                         entry("FILENAME=%s", csrFilePath.c_str()));
         elog<InternalFailure>();
     }
@@ -67,7 +67,7 @@
     int ret = PEM_write_bio_X509_REQ(bio.get(), x509Req.get());
     if (ret <= 0)
     {
-        log<level::ERR>("Error occured while calling PEM_write_bio_X509_REQ");
+        log<level::ERR>("Error occurred while calling PEM_write_bio_X509_REQ");
         elog<InternalFailure>();
     }