Rename flush-cache.py to flush-cache, and rearrange the code a bit.

It was working fine, but the style wasn't exactly the way I like it, because
I'm unnecessarily picky. :)

Also, removed the file extension since we should probably learn from the
fact that it's already been rewritten once from one language to another.
Who knows, maybe it will be again someday.

t/deps/basic/test.do

@@ -1,10 +1,10 @@
 rm -f *.out *.log
 
-../../flush-cache.py
+../../flush-cache
 redo-ifchange 1.out 2.out
 [ "$(cat 1.log | wc -l)" -eq 1 ] || exit 55
 [ "$(cat 2.log | wc -l)" -eq 1 ] || exit 56
-../../flush-cache.py
+../../flush-cache
 touch 1.in
 redo-ifchange 1.out 2.out
 [ "$(cat 2.log | wc -l)" -eq 1 ] || exit 58

t/deps/dirtest/test.do

@@ -1,11 +1,11 @@
 rm -f log dir1/log dir1/stinky
 touch t1.do
-../../flush-cache.py
+../../flush-cache
 redo t1
 touch t1.do
-../../flush-cache.py
+../../flush-cache
 redo t1
-../../flush-cache.py
+../../flush-cache
 redo-ifchange t1
 C1="$(wc -l <dir1/log)"
 C2="$(wc -l <log)"

t/deps/doublestatic.do

@@ -3,7 +3,7 @@ rm -f static.log
 redo static1 static2
 
 touch static.in
-../flush-cache.py
+../flush-cache
 redo-ifchange static1 static2
 
 COUNT=$(wc -l <static.log)

t/deps/gentest.do

@@ -1,19 +1,19 @@
 rm -f genfile2 genfile2.do genfile.log
 
 echo echo hello >genfile2.do
-../flush-cache.py
+../flush-cache
 redo genfile1
 
 # this will cause a rebuild:
 #      genfile1 depends on genfile2 depends on genfile2.do
 rm -f genfile2.do
-../flush-cache.py
+../flush-cache
 redo-ifchange genfile1
 
 # but genfile2.do was gone last time, so genfile2 no longer depends on it.
 # thus, it can be considered up-to-date.  Prior versions of redo had a bug
 # where the dependency on genfile2.do was never dropped.
-../flush-cache.py
+../flush-cache
 redo-ifchange genfile1
 
 COUNT=$(wc -l <genfile.log)

t/deps/test1.do

@@ -6,7 +6,7 @@ if [ -e t1a ]; then
 else
 	BEFORE=
 fi
-../flush-cache.py
+../flush-cache
 redo-ifchange t1a  # it definitely had to rebuild because t1dep changed
 AFTER="$(cat t1a)"
 if [ "$BEFORE" = "$AFTER" ]; then