added helper script for deb package's git hash

debian/changelog

@@ -1,9 +1,5 @@
-olive-editor (18.11.13bionic1-1) bionic; urgency=low
+olive-editor (201902160026-0ac9dd9+805~ubuntu19.04.1) disco; urgency=low
 
-  * Initial Release
-  * Included missing dep
-  * Included another missing dep
-  * Updated source to dd55b97
-  * Updated source to 6a38cd0
+  * Auto build.
 
- -- Olive Team <itsmattkc@gmail.com>  Fri, 13 Nov 2018 10:04:05 +1100
+ -- Launchpad Package Builder <noreply@launchpad.net>  Sat, 16 Feb 2019 00:26:45 +0000

debian/gitfromlog.sh

@@ -0,0 +1,3 @@
+# A simple script to extract the Git hash from an auto-generated debian/changelog
+
+grep -Po '(?<=-)(([a-z0-9])\w+)(?=\+)' $1

olive.pro

@@ -34,7 +34,7 @@ system("which git") {
     # Fallback for Ubuntu/Launchpad (extracts Git hash from debian/changelog rather than Git repo)
     # (see https://answers.launchpad.net/launchpad/+question/678556)
     isEmpty(GITHASHVAR) {
-        GITHASHVAR = $$system(grep -Po '(?<=-)(([a-z0-9])\w+)(?=\+)' debian/changelog)
+        GITHASHVAR = $$system(sh $$PWD/debian/gitfromlog.sh $$PWD/debian/changelog)
     }
 
     DEFINES += GITHASH=\\"\"$$GITHASHVAR\\"\"