Align on writing "SHA" in "allowTipSHA1InWant"
Align on writing "SHA" in "allowTipSHA1InWant"

Even if git-config key names are case-insensitive, align on writing
"allowTipSHA1InWant" with upper-cased "SHA" as that is how Git upstream
[1] and Gerrit code [2] do it.

[1] https://git-scm.com/docs/git-config#git-config-uploadpackallowTipSHA1InWant
[2] https://gerrit.googlesource.com/plugins/download-commands/+/refs/heads/master/src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java#42

Change-Id: Ie28ceec4703e22d696a3601a0e61ad52ca121b29

GerritCodeReview/plugins_download-commands