Try and fail to get condor_dagman_metrics_reporter to build on windows #3532

isspace redefined to is_space in b963f58. This seems like a bad idea.

Check for curl to build metrics reporter. This failed on Solaris in
batlab, and seems to cause linking problems on Windows.

Do not build dagman_metrics_reporter on windows (see above).  Windows
linker is not the most helpful tool in the world, and debugging is
difficult since NMI deletes everything on error.
Set duration of condor_dagman_metrics_reporter from configuration #3532

Now condor_dagman sets the duration of condor_dagman_metrics_reporter
using the value of the DAGMAN_PEGASUS_REPORT_TIMEOUT configuration
variable.
Simplify error handling by using exceptions #3532

Write out log of what we are doing, for debugging.  Print the
environment too.
Sleep a bit if we failed to contact a server #3532

Network admins might get angry if we issue 30 connect requests per
second, over and over for 100 seconds.