_create_or_patch_scmbrc is not noclobber safe



```
draistrickmini:~/.scm_breeze(master)%% set -o noclobber
draistrickmini:~/.scm_breeze(master)%% update_scm_breeze
From git://github.com/ndbroadbent/scm_breeze
 * branch            master     -> FETCH_HEAD
Current branch master is up to date.
-bash: /var/folders/lh/pq0p3b310135b42_9b7mmybc0000z8/T/tmp.XXXXXXXXXX.rGcYfnaw: cannot overwrite existing file
-bash: /var/folders/lh/pq0p3b310135b42_9b7mmybc0000z8/T/tmp.XXXXXXXXXX.rGcYfnaw: cannot overwrite existing file
draistrickmini:~/.scm_breeze(master)%% set +o noclobber
draistrickmini:~/.scm_breeze(master)%% update_scm_breeze
From git://github.com/ndbroadbent/scm_breeze
 * branch            master     -> FETCH_HEAD
Current branch master is up to date.
```


Easily resolved by overriding noclobber when we write out the patch file with >| instead of >

(...another solution might be to use a more unique tmpfile at https://github.com/ndbroadbent/scm_breeze/blob/master/lib/scm_breeze.sh#L41 to avoid the need to clobber, but I didnt verify that.

tested locally with bash, and a quick zsh verification of >| functionality with 5.0.2