[ck2cti] Fix handling of reaction units settings not on last line

Fixes a regression introduced in d56b6205fa.

interfaces/cython/cantera/ck2cti.py

@@ -1316,6 +1316,8 @@ class Parser(object):
 
         # Note that the subsequent lines could be in any order
         for line in lines[1:]:
+            if not line.strip():
+                continue  # blank line, or (erased) units field
             tokens = line.split('/')
             parsed = False
 

test/data/pdep-test.inp

@@ -118,13 +118,13 @@ PLOG / 100  1.28E+06    1.71    9774 /
 
 ! PLOG with duplicate rates, negative A-factors, and custom energy units
 H+R3=P3A+P3B 1.0    0.0 0.0
+units / kcal/
 plog / 0.001315789  2.44E+10    1.04    3.980 /
 plog / 0.039473684  3.89E+10    0.989   4.114 /
 plog / 1    3.46E+12    0.442   5.463 /
 plog / 10   1.72E+14    -0.01   7.134 /
 plog / 100  -7.41E+30   -5.54   12.108 /
 plog / 100  1.90E+15    -0.29   8.306 /
-units / kcal/
 
 ! Degenerate PLOG with a single rate expression and custom quantity units
 H+R4=H+P4 1.0 0.0 0.0