Revert r273099 "If the revision number starts with r, drop it. It will get added back"

This doesn't seem to work with Bash:

$ /work/llvm/utils/release/merge.sh --proj llvm --rev r275870
/work/llvm/utils/release/merge.sh: line 34: ${$1#r}: bad substitution

I get the same error with and without a leading 'r'.

llvm-svn: 275898

utils/release/merge.sh

@@ -31,7 +31,7 @@ while [ $# -gt 0 ]; do
     case $1 in
         -rev | --rev | -r )
             shift
-            rev=${$1#r}
+            rev=$1
             ;;
         -proj | --proj | -project | --project | -p )
             shift