Fix missing ECC update error log

This commit fixes ECC update error log. Currently, when vpd-tool
writeKeyword option fails due to failure in updating the record ECC in
ipz parser's writeKeywordToHardware method, an ECC exception message is
thrown up the call stack and gets logged in parser.cpp, however the
contents of the exception message get lost. This commit fixes the
missing error message.

Test:
```
- Ensure ECC update fails for given record
- Execute vpd-tool writeKeyword
- Observe following error log:

Sep 08 16:08:30 p11bmc vpd-manager[1109]: FileName: /usr/src/debug/
openpower-fru-vpd/1.0+git/vpd-manager/src/parser.cpp, Line: 226 Update
VPD Keyword failed for : VINI:PN failed due to error: Error while
updating keyword's value on hardware path /sys/bus/i2c/drivers/at24/
7-0050/eeprom, error: ECC update failed with error -1
```

Change-Id: I7a4ae822121d26618d5952f518f99d006d74441b
Signed-off-by: Souvik Roy <souvikroyofficial10@gmail.com>
diff --git a/vpd-manager/src/ipz_parser.cpp b/vpd-manager/src/ipz_parser.cpp
index 8210ed3..1998263 100644
--- a/vpd-manager/src/ipz_parser.cpp
+++ b/vpd-manager/src/ipz_parser.cpp
@@ -613,7 +613,8 @@
 
     if (l_eccStatus != VPD_ECC_OK)
     {
-        throw(EccException("ECC update failed with error " + l_eccStatus));
+        throw(EccException(
+            "ECC update failed with error " + std::to_string(l_eccStatus)));
     }
 
     auto l_recordECCEnd = std::next(l_recordECCBegin, i_recordECCLength);