Merge pull request ESMCI#1968 from jedwards4b/add_comp_root_dir_vars

add comp_root_dir vars so that only one change is required to move a …

Add COMP_ROOT_DIR_ variables so that a component can be moved with the change of a single cime variable.
Test suite: scripts_regression_tests.py, ERS.f09_g17.B1850.cheyenne_intel.allactive-defaultio
Test baseline:
Test namelist changes:
Test status: bit for bit
Fixes

User interface changes?:

Update gh-pages html (Y/N)?:

Code review: