This PR has three changes:
1) Fixing --permanent flag:
The previous algorithm looped over the values of PATH 4 times to check conditions while these conditions are the opposite of each other. Also, the result did not include all the parts in the whole_path.
I have combined these loops and fixed the algorithm, so no path is lost. Now using --permanent the PATH and Env variables are correctly updated.
2) Fixing --system flag:
Now, the system flag does not cause the PATH values to be overwritten/clobbered. The PATH/Env variables are correctly updated.
3) Fixing flagless flag:
When no flag is provided the value of process/shell is correctly updated and preserved.
This adds the tests for all the situations.
Fixes#634Fixes#645
40780130aa