Fix a small bug in the MIB compiler when building dependencies

[toland]

When compiling a dependency with a MIB file the generated hrl file is left in the root project directory in a file called "include". This has the perverse effect of messing up the search path for include files causing any dependencies with files in their "include" directory to fail to build after that.

[ferd]

+1. Any chance a test could be added for this?

[toland]

Sure. I will do that and update the PR.

[toland]

OK, I updated the tests and verified that the old code fails and the new code passes.

[talentdeficit]

related to #909 maybe?

[ferd]

Thanks for the contribution!

@talentdeficit yeah they seem related.

[talentdeficit]

i'll investigate whether we still need #909 now that this is merged

[goertzenator]

This PR does subsume 909, however there's a problem with this one: the MIB includes are being placed in the wrong directory.

This PR places the MIB includes into priv/mib/include, whereas rebar2 and erlang.mk places them in the application include directory. IMO this should be corrected to fall in line with that precedent.

Details:

1. This function in rebar2 show the cleaning out of generated MIB includes from include.
2. erlang.mk does the same because I use it and the MIB includes definitely land in include.
3. I couldn't find any OTP documentation that explicitly specifies where the MIB includes are supposed to go. I think everyone just assumes include.

[talentdeficit]

ok. if rebar3 and erlang.mk both agree it should go in include i will try to ensure it is present there