remove artificial minimum LAI value

[ckoven]

Removes the artificial minimum LAI of 0.1 that is being used in the canopy code, which was there at some point to provide stability. Hopefully we can get rid of it.

fixes #261

Expectation of Answer Changes:

expected to be answer changing.

Checklist:

• My change requires a change to the documentation.
• I have updated the in-code documentation .AND. (the technical note .OR. the wiki) accordingly.
• I have read the CONTRIBUTING document.
• FATES PASS/FAIL regression tests were run
• If answers were expected to change, evaluation was performed and provided

Test Results:

Not yet tested. Expectation is that it will not be bit for bit.

CTSM (or) E3SM (specify which) test hash-tag:

CTSM (or) E3SM (specify which) baseline hash-tag:

FATES baseline hash-tag:

Test Output:

[rgknox]

Looks pretty straightforward.

[rgknox]

All expected PASS

/glade/scratch/rgknox/clmed-tests/no_min_lai-ctsm5.1.dev025-C2094348b-Ff1842374.fates.cheyenne

(had to re-run one test:)
/glade/scratch/rgknox/ERP_Ld3.f09_g17.I2000Clm50Fates.cheyenne_intel.clm-FatesColdDef.retry-string-format