Save full file path to pot files

As requested here:
http://nabble.documentfoundation.org/libreoffice-l10n-Pootle-source-file-paths-not-available-anymore-td4229127.html

This adds the full source file path in case of .hrc and .ui files
to the generated pot, relatie to srcdir. So instead of
personalization.hrc:31
we can have
cui/inc/personalization.hrc:31
for better context for translators.
Since this is only in comment this will not change the translated
status of strings.
TODO: the other file formats we use are not affected by this.

Change-Id: Id436d66698c93e07c46bf9c20601c5b480eadd0b
Reviewed-on: https://gerrit.libreoffice.org/46591Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Andras Timar <andras.timar@collabora.com>

solenv/bin/hrcex

@@ -30,6 +30,6 @@ with open(ofile, "a") as output:
             keyid = entry.msgctxt + '|' + entry.msgid
             print >> output, '#. ' + polib.genKeyId(keyid)
             location = entry.occurrences[0][0]
-            location = os.path.basename(location)
+            location = os.path.relpath(location, os.environ['SRCDIR'])
             entry.occurrences[0] = location, entry.occurrences[0][1]
             print >> output, entry

solenv/bin/uiex

@@ -30,6 +30,6 @@ with open(ofile, "a") as output:
             keyid = entry.msgctxt + '|' + entry.msgid
             print >> output, '#. ' + polib.genKeyId(keyid)
             location = entry.occurrences[0][0]
-            location = os.path.basename(location)
+            location = os.path.relpath(location, os.environ['SRCDIR'])
             entry.occurrences[0] = location, entry.occurrences[0][1]
             print >> output, entry