Support Git v1.7

Some options used did not work with earlier versions of Git.  For example,
options with a value must be specified as a single argument.  Make small
changes to work with older versions of Git (possibly earlier than v1.7).

Issue: #38

Author: ColMelvin

bin/git-svn-diff

@@ -224,10 +224,10 @@ sub getFirstCommitBeforeRevision {
 	my $revision = shift;
 	fatal "Invalid revision string: $revision" if $revision =~ /\D/;
 
-	my $time = eval { command_oneline("log", "--all", "--format=format:%ci", "--max-count=1", "--grep", "^git-svn-id: .*\\\@$revision\\b") };
+	my $time = eval { command_oneline("log", "--all", "--format=format:%ci", "--max-count=1", "--grep=^git-svn-id: .*\\\@$revision\\b") };
 	return undef unless $time;
 
-	my $commit = eval { command_oneline("log", "--before", $time, "--format=format:%H", "--max-count=1") };
+	my $commit = eval { command_oneline("log", "--before=$time", "--format=format:%H", "--max-count=1") };
 	while (getSvnRevision($commit) > $revision) {
 		($commit) = getParentCommits($commit);
 	}
@@ -244,7 +244,7 @@ sub getCommitFromRevision {
 	# are added.  This corresponds to the git "empty tree".
 	return getGitEmptyTree() if $revision == 0;
 
-	return eval { command_oneline("log", "--format=format:%H", "--max-count=1", "--grep", "^git-svn-id: .*\\\@$revision\\b") };
+	return eval { command_oneline("log", "--format=format:%H", "--max-count=1", "--grep=^git-svn-id: .*\\\@$revision\\b") };
 }
 
 # Returns the commit of the given revision, accepting special SVN keywords,
@@ -256,7 +256,7 @@ sub getCommitFromSvnIdentifier {
 		my @files;
 		@files = @_ unless $revision eq "BASE";
 
-		my $commit = eval { command_oneline("log", "--format=format:%H", "--max-count=1", "--grep", "^git-svn-id: ", "--", @files) };
+		my $commit = eval { command_oneline("log", "--format=format:%H", "--max-count=1", "--grep=^git-svn-id: ", "--", @files) };
 		($commit) = getParentCommits($commit) if $revision eq "PREV";
 		return $commit;
 	}
@@ -274,7 +274,7 @@ sub getSvnRevision {
 
 	return 0 if $commit eq getGitEmptyTree();
 
-	my $body = eval { command("log", "--format=format:%B", "--max-count=1", $commit, "--", @files) };
+	my $body = eval { command("log", "--format=format:%b", "--max-count=1", $commit, "--", @files) };
 	return undef unless $body;
 
 	return $1 if $body =~ m/^git-svn-id:\s+[^@]+\@(\d+)\b/m;