Fix #1102, Correct return value bug in VxWorks OS_ShellOutputToFile_Impl

[thnkslprpt]

Checklist

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

• Fixes Return OS_ERROR if OS_ObjectIdGetById fails in vxworks OS_ShellOutputToFile_Impl #1102
  • Corrects use of ReturnCode (instead of Return) to hold result of OS_OpenCreate()
  • Moves call to OS_ObjectIdGetById() out before the if to make code clearer (and remove the side-effect from the if condition)
  • Moves if (Result == OK) to inside the block, immediately after the one and only assignment to the Result variable (this check being outside that block was part of what caused the mixed-up OSAL/VxWorks returns previously)
  • Sets ReturnCode to OS_ERROR if shellGenericInit() does not return OK - thus correcting the behavior of the function (and the coverage test) to actually return an error if that call fails
  • Updated the coverage test return value from OS_SUCCESS to OS_ERROR when OS_ObjectIdGetById() is seeded with an error return

Testing performed
GitHub CI actions all passing successfully (incl. Build + Run, Unit/Coverage Tests etc.).

Expected behavior changes
OS_ShellOutputToFile_Impl() will actually return an error on all failure cases now.
Function logic and flow is clearer now - easing future maintenance.

Contributor Info
Avi Weiss @thnkslprpt