Add semicolon to curly brace group in main Makefile

This semicolon is technically required by POSIX shell and indeed causes a
syntax error with e.g. bash-2.04.0.  Cf.

  http://www.opengroup.org/onlinepubs/000095399/utilities/xcu_chap02.html#tag_02_09_04_01

Signed-off-by: Mark Drago <markdrago@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -1557,7 +1557,7 @@ endif
 		ln "$$execdir/git-add$X" "$$execdir/$$p" 2>/dev/null || \
 		ln -s "git-add$X" "$$execdir/$$p" 2>/dev/null || \
 		cp "$$execdir/git-add$X" "$$execdir/$$p" || exit; \
-	  done } && \
+	  done; } && \
 	./check_bindir "z$$bindir" "z$$execdir" "$$bindir/git-add$X"
 
 install-doc: