remove spurious executable permissions on files

Fedora's rpmlint complains that some of the source code files in the
tree happen to be executable. Remove the execute bits from these files
to resolve the rpmlint warning.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
Merge pull request #1061 from kdreyer-inktank/rm-execute-bit-src

remove spurious executable permissions on source code files

Reviewed-by: Sage Weil <sage@inktank.com>