Remove extra newline from Kekulize error message.

[xavierholt]

The log message for a Kekulization failure had an extra newline. This removes it.

Example of the old behavior:

[01:01:51] Can't kekulize mol.  Unkekulized atoms: 6 7 8 9 10

[01:01:51] Explicit valence for atom # 2 H, 2, is greater than permitted
[01:01:51] Explicit valence for atom # 2 H, 2, is greater than permitted
[01:01:51] Explicit valence for atom # 2 H, 2, is greater than permitted
[01:01:51] Can't kekulize mol.  Unkekulized atoms: 17 18 19 21 22

[01:01:51] Explicit valence for atom # 2 H, 2, is greater than permitted
[01:01:51] Can't kekulize mol.  Unkekulized atoms: 8 10 12 15 18

[greglandrum]

Thanks @xavierholt!