improved cache key

Keeping the human readable part, the shasum should be on the origin url
rather than the repo path.  This way if multiple repos share the same
project name and same origin, they share the cached check.  This also
means that when the origin is changed then cache invalidates and we'll
immediately go off to look at the new origin.

Author: dbrinegar

bin/git_cautious_check_remote

@@ -3,6 +3,10 @@
 # Intended to guard against this machine auto-bombing a remote repo.
 # Will meter out remote checks to one per hour while no remote updates.
 
+# cache file is part human reable, pulled from the gitDir path, and part a low
+# collision hash made from the origin.url.  This means cache will refresh
+# whenever the repo base folder is renamed or origin is changed.
+
 # to show debug output, invoke like so:
 # DEBUG=1 git_cautious_check_remote
 
@@ -15,7 +19,8 @@ then
   exit 1
 fi
 
-if ! git config --get remote.origin.url >/dev/null 2>/dev/null
+remote=$( git config --get remote.origin.url 2>/dev/null)
+if [ $? != 0 -o -z "$remote" ]
 then
   [ $DEBUG ] && echo no upstream in this git repo
   exit 1
@@ -42,7 +47,7 @@ repoName=$( printf "%s" "$gitDir" | sed -e 's,/[^/]*$,,' -e 's,.*/,,g' )
 [ $DEBUG ] && echo repoName: $repoName
 
 
-flagFile="${repoName}-$( printf %s $gitDir | shasum | head -c 8 )"
+flagFile="${repoName}-$( printf %s $remote | shasum | head -c 8 )"
 flagFile="/tmp/${me}/${flagFile%% *}"
 
 [ $DEBUG ] && echo flagfile: $flagFile