Separate Makefile targets for relative and absolute RPM paths

[zrhoffman]

What does this PR (Pull Request) do?

Before #5653, you could build a single RPM by running make cache/traffic_ops_ort.rpm or make traffic_monitor/traffic_monitor.rpm, etc. and these Makefile targets were available to shell completion.
As of #5653, no RPM targets are completable in the shell and the only completable targets are the phony ones: all, build-builders, clean, debug, native, nearly-all, pull-builders, and very-clean.
This PR re-adds completion for those relative RPM targets but does not add them to the all target.

• This PR is not related to any Issue

Which Traffic Control components are affected by this PR?

• CDN in a Box

What is the best way to verify this PR?

In the CDN in a Box directory:

• Run make to verify that the all target still works
• Run make traffic_ops/traffic_ops.rpm and verify that the RPM ends up at infrastructure/cdn-in-a-box/traffic_ops/traffic_ops.rpm

In the main project directory:

• Run make -f infrastructure/cdn-in-a-box/Makefile traffic_ops/traffic_ops.rpm and verify that the RPM ends up at infrastructure/cdn-in-a-box/traffic_ops/traffic_ops.rpm and not traffic_ops/traffic_ops.rpm

If this is a bug fix, what versions of Traffic Control are affected?

• master (c928be0)

The following criteria are ALL met by this PR

• Building RPMs for CDN in a Box and building/running CDN in a Box itself is a sufficient test for the CiaB Makefile
• Bugfix, documentation is unnecessary
• An update to CHANGELOG.md is unnecessary
• This PR includes any and all required license headers
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information

[ocket8888]

For the record, after #5653 you can still make individual RPMs, even if shell completions have a hard time with it

[zrhoffman]

For the record, after #5653 you can still make individual RPMs, even if shell completions have a hard time with it

Not with the same command, I can't. This is what I get:

[user@computer cdn-in-a-box]$ make traffic_ops/traffic_ops.rpm
make: *** No rule to make target 'traffic_ops/traffic_ops.rpm'.  Stop.

make $(realpath traffic_ops/traffic_ops.rpm) works, but that takes awhile to type because there's no shell completion.

[ocket8888]

What's your make version? Works fine for me:

$ make traffic_ops/traffic_ops.rpm
make: Nothing to be done for 'traffic_ops/traffic_ops.rpm'.
$

[zrhoffman]

What's your make version? Works fine for me:

$ make traffic_ops/traffic_ops.rpm
make: Nothing to be done for 'traffic_ops/traffic_ops.rpm'.
$

Yes, but remove traffic_ops/traffic_ops.rpm and try again.

I'm using GNU Make 4.3

[ocket8888]

oh, you're right. Man, that's weird...

[zrhoffman]

Force-pushed to reword the commit message

[ocket8888]

This works fine, and if there are any negative consequences to having multiple (identical) recipes for the same file, I can't think what they are.