build_zip step in winx64-packages and win32-packages buildbot builders fails sporadically due to an error in SignTool

187>EXEC : SignTool error : The specified timestamp server either could not be reached

187>  or returned an invalid response.

187>  	This may happen if you specify an RFC 3161 timestamp URL but used

187>  	the /t option or you specified a legacy Authenticode timestamp URL

187>  	but used the /tr option.

187>EXEC : SignTool warning : Signing succeeded, but an error occurred while attempting to

187>  

187>  Number of files successfully Signed: 1

187>  

187>  

187>  Number of warnings: 1

187>  

187>  

187>  	timestamp: C:/buildbot/winx64-packages/build/mariadb-10.0.15/storage/sequence/RelWithDebInfo/ha_sequence.dll

187>  

187>  CMake Error at C:/buildbot/winx64-packages/build/mariadb-10.0.15/storage/sequence/cmake_install.cmake:40 (MESSAGE):

187>    Error signing

187>    'C:/buildbot/winx64-packages/build/mariadb-10.0.15/storage/sequence/RelWithDebInfo/ha_sequence.dll'

187>  Call Stack (most recent call first):

187>    C:/buildbot/winx64-packages/build/mariadb-10.0.15/cmake_install.cmake:68 (INCLUDE)

187>  

187>  

187>EXEC : CPack error : Error when generating package: MySQL

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: The command "setlocal

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: cd C:\buildbot\winx64-packages\build\mariadb-10.0.15

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: if %errorlevel% neq 0 goto :cmEnd

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: C:

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: if %errorlevel% neq 0 goto :cmEnd

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: "C:\Program Files (x86)\CMake 2.8\bin\cpack.exe" -C RelWithDebInfo --config ./CPackConfig.cmake

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: if %errorlevel% neq 0 goto :cmEnd

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: :cmEnd

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: endlocal & call :cmErrorLevel %errorlevel% & goto :cmDone

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: :cmErrorLevel

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: exit /b %1

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: :cmDone

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: if %errorlevel% neq 0 goto :VCEnd

187>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.CppCommon.targets(113,5): error MSB3073: :VCEnd" exited with code 1.