Cleanup trailing whitespaces and indentation that uses spaces before tabs

Correct spacing to fix warnings reported by
git diff --check 4b825dc642cb6eb9a060e54bf8d69288fbee4904 HEAD

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
diff --git a/strace-graph b/strace-graph
index a642e56..6a04ac2 100755
--- a/strace-graph
+++ b/strace-graph
@@ -308,9 +308,9 @@
 	} elsif ($$elem[0] eq 'FORK') {
 	    if ($i == 1) {
                 if ($lead =~ /-$/) {
- 		    display_pid_trace($$elem[1], "$lead--+--");
+		    display_pid_trace($$elem[1], "$lead--+--");
                 } else {
- 		    display_pid_trace($$elem[1], "$lead  +--");
+		    display_pid_trace($$elem[1], "$lead  +--");
                 }
 	    } elsif ($i == @seq) {
 		display_pid_trace($$elem[1], "$lead  `--");
@@ -336,4 +336,3 @@
 
     display_pid_trace($startpid, "");
 }
-