Pass version from configure to myproxy.h

It seems to be easily forgotten to change the version information in myproxy.h. This sets it automatically from configure. (MYPROXY_VERSION_MICRO is still 0, even though the versio is 6.1.9.)

I'm not sure what to do about MYPROXY_VERSION_DATE which contains "v6.1 Oct 2014". The version part coulld be set from configure, but what about the month and year?