test-convert-cvs: add a sleep to make test more stable

The recent addition of fuzzy tests introduced a new cvs commit which sometimes
fails.

This adds a sleep to make sure that cvs notices that the file has changed,
similar to how it is done in other tests.

tests/test-convert-cvs

@@ -134,6 +134,7 b' cd ..'
 
 echo % commit new file revisions with some fuzz
 cd src
+sleep 1
 echo f >> a
 cvscall -q commit -mfuzzy . | grep '<--' |\
     sed -e 's:.*src/\(.*\),v.*:checking in src/\1,v:g'